Cuyuna 215 R/D, 430 R/D, ULI 02, Hi-Performance 430 Engine OWNER'S MANUAL

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OWNER'S MANUAL
Ro E AN Nh AER AA AE EA AA a sa As A e ra LV eT a Aa Se
LIMITED WARRANTY
Cuyuna Engine Company (hereinafter “Cuyuna”) extends a Limited
Warranty on each new Cuyuna engine utilized in a product by a
recognized manufacturer (0.E.M.), that has complied with Cuyuna's
engine installation qualification procedure. Cuyuna s address con-
cerning warranty matters is: Cuyuna Engine Company, P.O. Box
116, Crosby, Minnesota 56441, ATTN: Customer Service Depart-
ment, but all claims must be submitted through the O.E.M. or
through a “Cuyuna Designated Service Dealer”.
Cuyuna's Limited Warranty is limited to the original purchaser of
the O.E.M. product and is not transferable to subsequent owners.
Cuyuna warrants ONLY the product it manufactures and does not
warrant that any other components are compatible for use with the
Cuyuna engine nor for any adverse effects that such other com:
ponents may have on Cuyuna engines. As a condition of the warran-
ty, the first purchaser must complete and mail the warranty card
HEN starting the engine for the first time.
The length of Cuyuna's warranty is for a period of ninety (90) days
after the Cuyuna engine ls first started by the original purchaser, or
one (1) year from the date the Cuyuna engine was sold to the
original purchaser, whichever is shorter. (This provision is tó give
the original purchaser a reasonable opportunity to assemble the
product, If such assembly Is necessary.)
During the warranty period Cuyuna will replace or repair, at its op»
tion, free of charge, any parts found by Cuyuna to be defective
1
because of a defect In material or workmanship. Related labor
charges will be performed at a flat rate as determined by Cuyuna.
Transportation charges are the responsibility of the purchaser.
The following VOIDS the Limited Warranty:
1. Failure by the purchaser or manufacturer to complete and mail
the warranty registration card to Cuyuna with the date the
engine was first started, and the date on which the product con-
taining the Cuyuna engine was purchased.
. Failure to perform maintenance required in the operators
manual.
. Any misuse, accident, abuse or negligent operation.
. Use of unapproved exhaust, carburetor or attachments to the in-
take system, such as air filters.
. Use of an unapproved oil or an approved oil in à mixture ratio
not approved by Cuyuna. Although any petroleum based oil that
has been B.I.A. TC-W rated is an approved oil, we recommend
“Cuyuna Oil”, Cuyuna recommends a 40:1 gasoline to oil mix-
ture ratio.
6. Any modification to the engine of any nature whatsoever.
7. Ene Cuyuna's recommended maximum engine speed
The following are NOT covered by the Limited Warranty:
1. Piston burning or piston seizure.
2. Spark plugs, ignition points or condensors or recoil ropes.
IN CONSIDERATION OF THE FOREGOING, ALL IMPLIED WAR-
RANTIES ARE LIMITED IN DURATION TO THE LIMITED WARRAN-
TY PERIOD AS SET FORTH ABOVE.
Some states do not allow limitations on how long an implied war-
ranty lasts, so the above limitation may not apply to you.
CUYUNA IS NOT LIABLE FOR ANY ACCIDENTAL OR CONSE-
QUENTIAL DAMAGES RESULTING FROM ANY BREACH OF ANY
WRITTEN OR IMPLIED WARRANTY FOR ANY CUYUNA PRODUCT.
Some states do not allow the exclusion or limitation of accidental
or conseguential damages, so the above limitation or exclusión
may not apply.
This warranty is intended to comply with the “Limited Warranty”
provisions of the Federal "Magnuson-Moss Warranty Federal Trade
Commission Improvement Act”, Any provisions of the warranty or
actions taken by Cuyuna pursuant to this warranty should be con-
strued accordingly. Cuyuna does not have an “Informal Dispute
Settlement Mechanism” as permitted under the Act.
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CUYUNA ENGINES
Manufactured by:
e Engine Company
P.O. Box 116
Crosby, MN 568441
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ENGINE IDENTIFICATION |
The engine serial number and model designation of your Cuyuna
engine are located on the sage name plate and stamped on the
upper crankcase half respectively.
These numbers are required to properly complete warranty claims
or to Insure obtaining the proper replacement part. No warranty will
be allowed on an engine if the serial number plate has been remov-
ed or tampered with.
CYLINDER DESIGNATION
To clarify service instructions, the cylinders are designated by the
all fr (1) and two (2). The cylinder mounted on the PTO end
of the crankcase (Figure 1) is designated as Number 1. The cylinder
mounted closest to the fan housing is designated as Number 2.
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у ENGINE SPECIFICATIONS
Model 215 RID 430 RID ULI-02
Bore 2.658" 2.658" 2.658"
Stroke 2.362” 2.362" 2.362"
Displacement 214cc 428cc 428cc
Comp. Ratio 12.5:1 12.5:1 12.5:1
Ignition System Nippendenso - Capacitor Discharge (CDI)
Ignition Timing 18°, 1.96mm or .070 - .078" BTDC
at 6000 RPM (see NOTE)
Reference Timing 28°, 4.42mm or .174" BTDC at 1800 RPM
(see NOTE)
Lighting System 150 watt unregulated - 32 volt AC
at 6000 RPM
Spark Plug Type NGK B8ES or equivalent
Spark Plug Gap 016" - .020" 035" - .040"
Base Mounting Holes| 7/16" - 14 UNG
Rotation Counter clockwise viewed from PTO end
Fuel Oil Mixture 40:1 (1 pint to 5 U.S. gallons)
Lubrication Regular leaded or premium unleaded and
Cuyuna 2-cycle oil ат
ENGINE WEIGHTS o
Model | 215 R/D 430 R/D ULI-02
Bare Engine RID _| 42/45/bs. — 65/68 Ibs. 58/61 Ibs.
E NOTE: The timing specification for all models, 430, 215 and
ULIN-02 Cuyuna oe laca with C.D. ignitions is 1.96mm or .078”
B.T.D.C. at 8000 RPM. To check ignition timing at a lower RPM, a
“Reference Timing" is used. Refer to the Cuyuna Service Manual
for specific instructions on ignition timing.
TWO-CYCLE ENGINE THEORY
INTAKE:
The first step in an engines work cycle is the INTAKE of fuel and air
from the carburetor. In order to get the mixture into the crankcase
area, there must be an opening (port) along with some kind of valve
to open and close the port. In the Cuyuna two-cycle engine, the
piston acts as the valve (this is otherwise known as a “piston
ported’ two-cycle engine). When the piston begins to move up in
the cylinder the movement creatas a partial vacuum or low pressure
area in the crankcase.
FIG 2
As the piston continues to ascend, the piston skirt uncovers the in-
take port (Figure 2). Since the fuel mixture will flow from a high
pressure area to a low pressure area, the crankcase and lower por-
tion of the cylinder are filled with a fresh fuel mixture. This fresh
mixture remains in the engine and completely fills the crankcase
and lower cylinder. The mixture is used to lubricate the crankshaft
main and needie bearings until the piston starts to descend and un-
covers the transfer ports.
TRANSFER:
The second step is the TRANSFER of the fresh fuel mixture In the
crankcase to the cylinder. Às the piston begins the downward
stroke, the fuel mixture in the crankcase is compressed. When the
piston moves privat the transfer ports, (Figure 3) the fuel mixture is
forced to the lower pressure area of the cylinder bora. This con-
tinues until the ports are completely uncovered and the piston ls al
bottom dead center (BDC).
FIG 3
The basic transfer port design has two important functions. The
transfer port must move the mixture from the crankcase to the
cylinder. Also, the transfer port must help the engine get rid of
(scavenge) exhaust gases from the cylinder. Before the transfer
port can operate correctly, the exhaust gases rush out of the
cylinder until the internal cylinder pressure equals external
pressure (ambient pressure). At this point the exhaust gases will
quit flowing. The transfer ports must aim the incoming fresh mix-
ture in such a way to aid the removal of any remaining burned
gases.
COMPRESSION AND IGNITION:
The third step in a two-cycle engine is COMPRESSION. Compres-
sion occurs only after all the poris in the upper part of the cylinder
are closed. At this point, the mixture is compressed by the upward
motion of the piston from bottom dead center (BDC).
FIG 4
As the piston reaches a specific predetermined point before top
dead center (B.T.D.C.), an electrical spark jumps the air gap be-
tween the center and ground electrode of the spark plug. (Figure 4)
This causes the compressed fuelfair mixture to ignite (burn). At nor-
mal cranking speeds the spark occurs at slightly before top dead
center (B.7.D.C.), however; when the engine reaches idle speeds the
ignition ang is at Its most advanced position (287 BTDC). As the
engine speed increases the ignition timing is retarded to 18° BTDC.
The spark is electronically controlled in current production Cuyuna
engines by the CDI unit.
EXPANSION (POWER):
The power stroke begins just after the ignition of the fuel mixture.
The burning gases expand and force the piston downward by exer-
ting the maximum combustion pressure on the piston dome. The
downward force is then transmitted through the connecting rod
and, because of the crankshaft design, is converted to radial mo-
tion. In a two-stroke engine the power stroke is completed when the
piston begins to clear the exhaust port opening.
FIG 5
EXHAUST:
The final step of the engine work cycle is the EXHAUST of the burn-
ed combustion gases from the cylinder through the exhaust port.
When the piston moves by the exhaust port (Figure 5) most of the
exhaust gases are expelled, however; some remain in the cylinder.
As the piston moves past the transfer ports, the incoming mixture
forces the remaining gases out of the cylinder.
OPERATING LIMITATIONS
Minimum recommended engine instruments for safe engine opera-
tions:
Cylinder Head Temperature Monitor 0-500°F scale
Tachometer 0 - 8000 APM scale
Operating RPM's:
Engine Idle (all models) 1500 - 2000 RPM
STATIC RPM WOT
ENGINE ENGINE COLD BHP/RPM
215 6750 20 h.p./6500 RPM
430 6500 35 h.p./8250 RPM
ULI-02 6500 35 h.p.16250 RPM
Hi-Performance 430 7050 43 h.p./6800 RPM
8
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EN NOTE: The aircraft propeller acts as an enginegovernor. For
proper engine operation the engine must be propped to achieve the
“Static RPM" corresponding to the particular engine model.
Operating Temperatures:
Maximum CHT (cylinder head temperature) ADO "F- ALL
Maximum EGT (exhaust gas temperature) 1275°F - ALL
(Cuyuna Exhaust)
Best Power EGT 1200°F- ALL
(Cuyuna Exhaust)
Ш NOTE: For accurate temperature indications, temperatures of
the #1 cylinder (see Cylinder Designation) must be monitored. See
“Temperature Monitoring” for placement of temperature sensors.
TEMPERATURE MONITORING
Temperatures of the #1 cylinder should be monitored for both trac-
tor and pusher applications.
Cylinder Head Temperature - CHT:
The CHT sensor must be used in place of spark plug gasket of the
#1 cylinder. Refer to section entitled “Operating Limitations’ for
proper operating temperatures.
Exhaust Gas Temperature - EGT: (Cuyuna Exhaust)
The EGT pres must be positioned so that it is one and one-half
(1%2") inches from the exhaust manifold flange gasket surface of
the #1 cylinder. Refer to section entitled “Operating Limitations”
for proper operating temperatures.
FUEL REQUIREMENTS
The two-cycle Cuyuna engine requires that oll be mixed with
gasoline for engine lubrication. Use clean, fresh, leaded regular or
unleaded premium automotive gasoline. The gasoline should have
a minimum pump octane of 88. Use genuine Cuyuna 40:1 oil or oil
that has been B.l.A. certified, TC-W rated. Recommended jetting
has been ascertained using the above fuels and olls.
MON. © The use of aviation gasoline, or other fuels:
Upset carburetion. --— A DA i"
Ш NOTE: It is imperative to maintain the correct fuel/oll ratio
(40:1). Too much oll will cause spark plug fouling, excessive smoke
and carbon build-up. Too little oil will cause engine damage from in-
adequate lubrication.
A WARNING A Always mix fuel and oil in a well ventilated area,
do not smoke. Never mix or add fuel to the fuel tank near an open
flame with the engine running or while the engine or exhaust
system is hot.
1. Put 2% gallons of gasoline in a five gallon container (U.S.
measure). ;
2. Add 16 fl. oz. of B.LLA., TC-W two-cycle engine oil.
3. Shake container vigorously.
N
4. Add the remalning 2% gallons of gasoline.
5. Agitate container thoroughly again.
6. Use a clean funnel with a fine metal screen to pour the fuel mix-
ture into Ha gas НЫ.
Fuel/Oi Ratio Divan of B. | A. TCW Gallons of Gasoline o Raced
40:1 19.2 6
40:1 16 5
40:1 13 4
40:1 9.5 3
40:1 8 2.5
40:1 6.5 2
40:1 3.2 1
BREAK-IN PROCEDURE
1. or the first three (3) gallons of fuel used in a new or rebuilt
una engine, mix twice the amount of B.LLA. TC-W rated oil
oh a given amount of fuel (20:1 mix ratio), than is indicated in
the section entitled, “Fuel Requirements”.
2. Run the engine for one-half %) hour under low load conditions
at various engine speeds (RPM). Do not exceed one-half (Va
throttle at this time, vary the throttle from idle to one-quarter (Va
to one-half (2) throttle settings for short periods (30 seconds
gan this time. This will assist in seating the piston rings prop-
arly.
3. For the next % hour of engine operation, do not run the engine
for sustained periods (more than 30 seconds) at throttle open-
ings in excess of 3 throttle. Continue to vary the throttle during
this break-in period.
4. After the engine has been run for one hour, it is recommended
that the cylinder heads be re-torqued while the engine is warm,
but NOT HOT.
5. Thé engine should be run on the ground for the first hour of ini-
tial break-in or for the time required to consume 1%: gallons of
the 20:1 fuel/oil mixture. When 1%: gallons of the 20:1 fuelloil
mixture has been used, top the fuel tank with 40:1 fuel/oil mix-
ture.
6. For the first ten hours of flight it Is suggested that the engine
not be run for sustained periods at throttle opening in excess of
34 throttle. Continue to vary the throttle during the first ten
hours of flight.
10
PRE-START INSPECTION
. Check the ignition - be sure it is in the OFF position.
Sama throttle control and release. Make sure throttle moves
reely.
Inspect exposed portions of throttle cable for signs of chaffing
and wear.
. Inspect air filter for signs of wear and security of attachment.
. Inspect carburetor for security of attachment.
. Inspect rubber flange for signs of fatigue.
. Inspect accessory mounting hardware for security.
. Inspect engine wire bundle for chaffing, shorts, clean and tight
connections.
. Inspect spark plug wires and spark plug connectors for chaff-
ing, shorts, breakage and tightness.
. Inspect fan drive Бей for tightness, cracks or Ta
me fan blades, stator blades and cooling fins for foreign
matter.
. Inspect case half to case half seal, cylinder base gaskets, PTO
uE seal, cylinder head gaskets, spark plugs for signs of
sakage.
13. Inspect engine mount bolts for security.
14. Inspect fuel line for looseness, swelling or cracks.
15. Inspect in-line fuel filter.
16. Inspect fuel system venting system.
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UTION e Engine and accessories me
STARTING PROCEDURES
Starting Procedures - COLD
1. Turn ignition to "ON", |
2. Actuate throttle control to be sure it is not sticking and return it
to idle position.
3. Set enrichner to the "ON" position.
4, Grasp recoil starter handle, pull slowly to engego the
mechanism, then pull sharply with HANDS OFF THROTTLE.
This is important!
5. After several pulls should engine fail to start, release enrichner
and repeat step 4. If engine still fails to start see "Flooded Start-
ing Procedure”.
Starting Procedures - WARM
. Turn ignition to "ON".
. Actuate throttle control to be sure it is not sticking.
. Set enrichner to "OFF" position.
. Actuate throttie control approximately ‘4 open.
. Grasp recoil starter handle, pull slowly to engage the
mechanism, then pull sharply.
. If engine fails to start after several pulls, actuate enrichner and
repeat pulling sequence with throttle in idle position.
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Starting Procedure - FLOODED
1. Be sure ignition is “ON”.
2. Be sure enrichner is "OFF".
3. Actuate throttle control to Vz throttle.
4. Grasp recoil starter handle, pull slowly to engage mechanism,
then pull sharply.
A WARNING A Holding the throttle control open will cause the
engine to rev up. Alrcraft must be restrained to avoid injury. Release
throttle control as soon as engine starts.
Ш NOTE: if engine still fails to start see “Trouble Shooting".
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Ш NOTE: For best engine performance the throttle opening should
be smoothly advanced from closed throttie to full throttle in not
LESS than THREE (3) SECONDS.
GENERAL SPARK PLUG INFORMATION
Spark Plug Selection:
Original equipment parts or their equivalent should always be used.
However, the heat range of the particular spark plug is of utmost im-
portance, because a spark plug with a heat range which is too high
will cause engine damage, one with a heat range which is too low,
will cause excessive fouling and malfunction. The spark plugs in-
stalled in your Cuyuna engine at the factory are the normal heat
range, which are best suited for all around normal service.
It prolonged low speed, light duty is expected, it is recommended
that a “hotter” spark plug be used to prevent spark plug fouling. It
must be remembered that the engine, when equipped with a spark
plug of a higher heat range, must be used in an extreme duty condi-
tion for only very short periods or not at all.
If prolonged high-speed or other heavy duty usage is anticipated
use a “colder” spark plug to prevent pre-ignition and piston failure.
Always start your new Cuyuna engine with factory installed spark
plugs. A new engine will sometimes cause temporary spark plug
fouling even though the heat range is correct, due to the 20:1
fuel/oil ratio used for break-in. TEAR
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E NOTE: Incorrect air/fuel ratio can often cause a spark plug to
appear to be too dark or too light in color. Before changing spark
plug heat ranges, be sure the carburetor is jetted correctly.
Spark Plug Reading:
Reading the firing end condition of the engine spark plugs is a
useful tool in determining proper engine operation. When taking
spark plug readings, 10 assist in carburetor adjustment (see section
antitied “Carburetor Adjustment”) a set of used, clean spark plugs
ОЕ be used. A new set of spark plugs will not provide accurate
readings.
Firing End Conditions:
Normal - Combustion deposits are slight and not heav enough to
cause any detrimental effect on engine performance. Color will be
brown to tan and have a minimal amount of electrode erosion.
Carbon Fouled - Soft, black, sooty deposits easily identifies this
plug condition. This is most often caused by an over-rich air/fuel
mixture. Check for proper operation of enrichner valve, clogged air
filter, proper carburetor jetting and adjustment.
Oil Fouled - Too much oil is entering the combustion chamber. This.
is often caused by APTO mixing of the fuel/oil mixtore Vars
fuelloil mixture ratio or by piston rings or cylinder walls that are
badly worn. A
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E NOTE: Oll will collect in the spark pl ugs GH angines installed in
the inverted position when not in use: It Is a good Idea to install an
old set of spark plugs on engines stored in the inverted position, to
prevent oil fouling. Vi
Overheated - A clean white insulator tip andlor excessive electrode
erosion indicates this spark plug condition. This is often caused by
over advanced Ignition timing, a lean fuel/air mixture or an engine
air leak. When these conditions prevail, even a plug of the. correct
heat range will overheat. hia
Worn - Good color (brown to tan) with exces sive electrode wear. The
voltage required to fire the pie will approximately double and will
continue to increase with additional use. Voltage requirement as
much as 100% above normal, may occur when the engine is quickly
accelerated. Poor engine performance and à loss In fuel economy
are trails of a worn spark plug.
13
Insulator Glazing - Glazing appears as a yellowish, varnish-like со!-
or. This condition indicates that spark plug temperatures have risen
suddenly during a hard, fast acceleration period. As aresult, normal
combustion deposits do not have an opportunity to fluff-off as they
normally do. Instead they melt to form a conductive coating and
mis-fire may occur.
Ash Fouling - A build-up of combustion deposits stemming primari-
ly from the burning of oil during normal combustion - normally non-
conductive. When heavier deposits are allowed to accumulate over
a period of time, they can “mask” the spark, resulting in a plug
misfire condition.
Splashed Fouled - Appears as “"spotted” deposits on the firing tip of
the insulator and often occurs after a long delayed tune-up. By-
peros of combustion may loosen suddenly when normal com-
ustion temperatures are restored. During hard acceleration, these
materials shed from the piston dome and are thrown against the
hot insulator surface, which may cause misfiring.
SPARK PLUG DATA
Engine | Type | SPARK PLUG
Model | ignition [Tight Duy [Normal Duly [Heavy Duly Plug Gap
2158/D| CDI NGK B7ES |NGK BSES _ |NGKBSES | 016.020
420RIDÍCDI — |NGK B7ES NGK B8ES | NGK B9ES 016-020
ULIL02| GDI N SK, B7ES | NGK BBES NGK B9ES 035-040
215R/D| CDI Champion N4C | Champion N3C | Champion N2 | 016-020
430A/D | CDI Champion N4C | Champion N3C | Champion N2 | 016-020
ULILOZ | CDI Champion N4C | Champion N3C | Champion N2 | .035-.040
215 [CDI [Bosch WSC _ |BoschW4C1 |BoschW3C | 016-020
430 |cni [Bosch WSC |Bosch WAC1 [BoschWac | 016-020
ULI-02|CDI | Bosch W5C | Bosch W4C1_ | Bosch WaC | 035-040
N NOTE: NGK spark plugs listed under the “Normal Duty"
pe pat are those which are installed at the Cuyuna factory. If
spark plug brands other than NGK are to be used, be sure the spark
plug heat range is equivalent to that of the original equipment spark
plugs installed on your Cuyuna engine.
№ NOTE: The spark plug should be checked for appearance and
gap after each ten (10) hours of use.
GENERAL CARBURETION
The Mikuni VM-type and BV-type carburetors used on current pro-
duction Cuyuna engines are calibrated for standard day, sea level
pparatien, Calibration was done using "Cuyuna" exhaust system,
“Unifilter” foam air filter and a “Cuyuna” fuel pump. The amount of
air drawn into the cylinders is influenced by such factors as the
altitude, the temperature, humidity, etc. This section is provided to
familiarize you with the carburetor systems and how to compensate
14
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for altitude and temperature changes. )
Ultralight aircraft engines are operated under a wide range of condi-
tions. From idling with the throttle valve remaining almost closed to
the full load with the throttle valve fully open. In order to meet the
requirements for the proper mixture ratio under these varying condi-
tions, a low speed fuel system (the pilot system) and a main fuel
system are provided in Mikuni VM-type and BV-type carburetors.
Mikuni VM-type Carburetors:
EXPLODED VIEW OF VM TYPE CARBURETOR
Nun Fon
)
1. Rubber Cap Throttle Cable
2, Cable Adjuster
3 Locknut, ‘Cable Adjuster
4, Top, Mixing Chamber
=, Gasket, Mixing Chamber Top
6. Spring, Throttle Valve
4, Plate, Needle Retainer
B. “E” Ring
9. Neadie
10, Throttle Valve
11, Needle Jet
12, Aubbet Cap, Starting System
13. Fitting, Starter System Plunger
14, Lever Assy, Starting System
15, Leal Spring, Lever Positioning
16. Spring, Starter Plunger
17. Plunger, Starting System
18. Bady, Mixing Chamber
19. Gasket, Float Chamber
FIG 6
RSS
BSSHELRSESSynnE
Low-Speed Fuel System (the pilot system):
FIG 7
16
Baffle Plate, Float Chamber
Prot Jet
Pin, Float Arm Hinge
Float Arm
Float
Float Chamber
Gasket, Float Chamber Plug
Plug, Float Chamber
Air Correction Jet
Screw, Air Adjusting
Spring, Air Adjusting Screw
Spring, Idle Adjusting Screw
screw, [die Adjusting
Gasket, Needle & Seat Assy
Meedie & Seat Aggy
Cup, Fuel Retaining
Main Jet
Plate, Vent Tube Retaining
Screw, Float Chamber
Hp EE RUE,
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Since the engine is operated with the throttle valve it closed at
idling or in the low speed range, the velocity of air flowing across
the needle jet (2) is slow. Consequently, a vacuum strong enough to
draw fuel from the needle jet in the main fuel system is not created.
The fuel supply during this low speed operation is controlled by
means of the pilot outlet (3) and the bypass (4). At idle when the
throttle valve is slightly opened, fuel metered by the pilot jet (5) 15
mixed with air adjusted in a proper amount by the air screw (6) and
is broken into fine particles (vapor). As the air screw Is turned in
(clockwise) closing off the pilot air inlet passage and allowing more
of the available vacuum to draw fuel from the bowl, the mixture is
made richer. As the air screw is turned out (counterclockwise)
allowing more air to be drawn through the pilot air inlet passage,
the mixture is made leaner.
The mixture is again mixed with air coming from the bypass and is
drawn into the pilot outlet to mix with air flowing through the main
bare (7). The fuel, mixed with air at this stage, then goes into the
engine. When the throttie valve is opened slightly during low speed
operation, the pilot outlet alone cannot supply the required fuel and
the shortage has to be made up with fuel drawn through the bypass.
The adjustment of the mixture ratio at this stage is made up by the
pilot jet and the pilot air screw. While at low speed operation if full
throttle is initiated a similar shortage of fuel exists, and during this
transition from low to medium or low to high the fuel again has to
be drawn from the bypass until enough vacuum can be created to
draw fuel from the main fuel system.
17
)
Main Fu... System:
On Mikuni VM-type carburetors, the pilot system and the main
system are of independent construction.
The fuel flow In these two systems is shown in Figure 8.
TOTAL AMOUNT
OF FUEL FLOW MAIN FUEL SYSTEM
FUEL FLOW
PILOT FUEL SYSTEM
—_— о x
=== = —
THROTTLE = VALVE OPENING(%] —m—
When the throttle valve is opened about ‘4 or more, the velocity of
air flowing past the needle jet (10) (Figure 9) increases and also the
vacuum increases to the point where fuel can be drawn in. When
the throttle valve (1) opening is between ‘4 and 3%, fuel passes
through the main jet (9) and after being metered in the clearance
between the needle jet and needle (11), it is mixed with air that is
dt the air jet (12) and automization of the fuel is ac-
erated.
18
FIG 9
8B NOTE: Mikuni VM-type carburetors used on Cuyuna engines do
not utilize an air metering jet (12). This has been deleted by the ven-
dor for Cuyuna's application.
The mixture is then drawn, after mixing with air flowing through the
main bore (7), into the engine in the optimum air-fuel ratio. During
this process of operation, the cut-away of the throttle valve serves
to control the vacuum (1/4 - 3/8 throttle) on the needle jet, thereby;
regulating the amount of fuel that is drawn into the engine. When
the throttle valve is opened more than % for high speed operation,
fuel is metered chiefly by the main jet.
Float System - VM- and BV-type Mikuni: (Figure 10)
The float system serves to maintain a constant level of fuel in the
bowl. Fuel flows through the needle valve (14) and enters the float
chamber (15). As the fuel enters the float chamber, the float (16)
moves upward to its pre-determined: level because of bouyancy.
When the fuel reaches the pre-determined level, the needle valve
begins to close due to the lever action of the float arm rising as the
float attains bouyancy, thus shutting off the supply of fuel.
ere iT Tye
tl AR a Lee ap E por A
19 M E A PO TE os EE pp
Lee fee Fe ES Ta
14 16) (15)
FIG 10
The fuel level in the bowl controls the amount of fuel which is
metered to make the optimum fuel mixture. For example, too high a
level allows more fuel than necessary to leave the needle jet
enrichening the mixture. Too low a level results in a leaner mixture,
as not enough fuel leaves the needle jel. Therefore, the pre-
determined fuel level should not be changed arbitrarily.
Ш NOTE: The diameter of the inlet valve seat of VM- and BV-type
Mikuni carburetors used on Cuyuna engines is 1.5mm, This is the
size required for use with a crankcase pulse actuated fuel pump.
Gravity feed fuel systems require a larger diameter inlet valve seat.
Starter System: (Figure 11)
In place of the choke the starter system is employed for Mikuni car-
buretors, In the starter type, fuel and air for starting the engine are
metered by entirely independent jets. The fuel metered oy the
starter jet (17) is mixed with air and is broken into tiny particles in
the emulsion tube (18). The mixture then flows into the plunger area
(19), mixes again with air coming from the air intake port for startin
and is delivered to the engine in the optimum air-fuel ratio throug
the discharge passage (21). The starter is opened and closed
20
— — == = =
through the means of the starter plunger (22). Since the ) arter type
is constructed so as to utilize the vacuum of the inlet passage (20),
it is important that the throttle valve is closed, while starting the
engine.
FIG 11
21
Mikuni Bv ype Carburetors: (Figure 12)
EXPLODED VIEW OF BV
EE TYPE CARBURETOR
Key
1. Carburetor Assembly 14. Screw 27. Packing (O-Ring)
2. O-Ring 15. Bracket 28. Float Chamber
3. Jet Block 18. Gasket 29. Lever
4. Pilot Screw 17. Pipe 30. Lock Washer
5. Spring 18. Nozzle 31. Nut
6. Pilot Jet 19. Main Jet 32. Packing
7. Hose 20. Jet Holder 33. Seal
8. Air Jet 21. O-Ring 34. Hose
9. Screw 22. Washer 35. Spring
10. Throttle Shaft 23. Bolt 36. Ring
11. Float 24. Spring 37. Throttle Valve
12. Float Pin 25. Plunger Assembly 38. Screw
13. Needle Assembly 26. Plunger Cap 39. Plate
22
SAH
idle System: (Figure 13) )
The idle system is responsible for metering the fuel/air mixture re-
quired to keep the engine running at idle and up to 1/8 throttle. The
system consists of a pilot jet, a pilot mixture screw to meter fuel, a
pilot air jet to meter air and a system of passages through the body
of the carburetor.
a AIR JET
, PILOT MIXTURE SCREW | /
BYPASS BLOCK | ^
| — PILOT JETS —MAIN DISCHARGE
| \ у
| i
HOZZLE
— MAIN JET
FIG 13
As the engine Idies, the throttle valve is nearly closed creating a low
pressure area behind the valve. The pilot outlet is located in this low
peas area. The low pressure area ad LN st draws fuel
rom the float bowl up through the Bllgt 161. 8. uel leaves the pilot
jet, It is mixed with air from the pilot air jet. This fuel-air mixture
passes the pilot mixture screw which meters the fuel-air mixture
entering the carburetor from the pilot outlet.
As the pilot mixture screw is turned In (clockwise) restricting the
pilot mixture passage, the pilot mixture is made leaner. As the pilot.
mixture screw Is turned out (counter-clockwise) opening the pilot 3
mixture passage, the pilot mixture is made richer.
23
Г =
of pf
LE
AA
я HT ==
Apr
Part Th. le System: (Figure 14)
Fuel Is delivered to the engine during part throttle operation
through the pilot jet and the bypass block.
FART THESTTLE
FIG 14
The part throttle system affects fuel discharge from 1/8 to 3/8 throt-
tle. As the throttle valve is opened and engine RPM Increases, the
additional fuel required from the carburetor is supplied from the
primary and secondary discharge ports of the bypass block. Air
from the pilot air jet is pre-mixed with the fuel from the pilot jet
enroute to the bypass block.
The bypass block has a letter stamped on its top surface, which in-
dicates its size. Care must be taken to ensure the correct size is
used when replacement is necessary. Each carburetor has one
bypass block that is correct.
High Speed System: (Figure 15)
The correct fuel/air mixture required by the engine during high
speed operation (3/8 throttle - wide open throttle) is delivered by the
high speed system and is metered by the main jet. Other com-
ponents which make up the an spead system are the main air jet
and main discharge nozzle. All components work together to pro-
vide the engine with the correct fuel/air mixture during high speed
operation.
24
HIGH SPEED
,— MAIN AIR JET
~ PILOT MIXTURE SCREW
BYTFASS BLOCK MAIN DISCHARGE
rma JET NOZZLE
wl
rp A
La AMM
i
15
I
Ay Fate
E me vi rie -
PER E ©
E
I
ve,
'— MAIN JET
FIG15
As the throttle valve reaches 3/8 throttle, fuel is drawn up through
the main discharge nozzle by the low pressure In the venturi. The
amount of fuel entering the main discharge nozzle is metered by the
main jet located at the nozzie end in the float bowl. Air is drawn
down through the top of the main discharge nozzle and is metered
by an air inlet = located at the top of the nozzle. The fuel and air
are pre-mixed in the main nozzle and is discharged into the car-
buretor bore.
Starter System: (Figure 16)
The Mikuni BV-type carburetor is equipped with an enrichment
valve instead of a conventional choke for cold starting. The system
consists of a starter jet, a starter plunger and a fuel passageway
from a well in the float bowl to the venturi.
25
And | STARTER PLUNGER
FIG 18 STARTER JET
As the starter plunger is lifted off its seat, it allows fuel to be drawn
from the float bowl up through the emulsion tube. The starter jet
meters the delivery of fuel into the emulsion tube. With the throttle
valve closed, almost all of the air drawn into the engine must pass
through the starting system passageways. This creates enough
suction to draw fuel into the mixing chamber where it is mixed with
air from the carburetor inlet. The rich mixture is then drawn into the
venturi and then into the engine. The throttle valve must remain in
the idle position when using the starting system to start a cold
engine. If the throttle valve is opened, the starter system will be
bypassed.
CARBURETOR ADJUSTMENT
Main Jet:
1. Select the largest main jet (the limit of a rich mixture) which will
allow the engine to run at “Static APM”, listed in the “Operating
Limitations” section for your engine (refer to main jet selection
charts for approximate jet sizes).
2. After the engine warms up, check CHT. CHT'S MUST REMAIN
BELOW THE MAXIMUM TEMPERATURE LISTED IN
OPERATING LIMITATIONS SECTION OF THIS MANUAL.
3. Run engine at full throttle for two - three minutes.
A WARNING A To avoid injury, stake aircraft stationary while
making main jet selection.
4. While the engine is running at full RPM, turn the ignition “OFF”
and hold the throtile open untill crankshaft stops rotating.
Remove spark plugs and note plug color. (See “General Spark
Plug Information’ section for spark plug reading).
26
5. Repeat steps 2 through 4 using different main jets until correct
spark plug color is noted.
MAIN JET SELECTION CHART
Altitude
Feet ENGINE: 430 RID EXHAUST: Cuyuna CARBURETOR: VM32
8000 | 230 220 210 200 | M0
6000 250 240 | 280 220 210
[4000 270 | 20 | 20 |. 240 230 —
2000 2060 | 20 | 270° | 260 _ 250
[Sea Level 310 300 | 2060 0 | a
Temp. °F | 0°-20° | 20°-40° | 40-60” | 60°-80° | 80° - 100° |
Altitude |
Feet ENGINE: 430 A/D EXHAUST: Cuyuna CARBURETOR: VM28
8000 |. 200 | 480 | 8 170 _160
| 6000 210 200 - 190 180 170
| 4000 20 | 20 _ 200 190 180
2000 230 220 | 210 | 200 — 190
| Sea Level 240 230 | 2» | 2 200
Temp. °F 0°-20° | 20°-40° | 40°-60° | 60°-80° | 80" - 100°
Altitude ENGINE: Hi-Performance
Feet EXHAUST: Cuyuna _ CARBURETOR: B34-32
8000 170 | 180 150 MO | 10
6000 | 180 | 170 160 450 — 140
4000 | 190 180 170 160 150
2000 | 200 | 190 | 18 | 1 180
Sea Level 210 200 190 | 180 170
Temp. "F 0°-20° | 20*-40° | 40°-60° | 60°-80° | 80-100"
Altitude
Feel ENGINE: 215 R/D EXHAUST: na CARBURETOR: B34-32
8000 150 140 1 1 11
5000 1 1 40 1
4000 170 160 150 140 130
2000 180 170 160 150 1
Sea Level 180 180 170 160 e
T Es: 5 0°-20" | 20°-40° | 40"- 60° | 60° - 80° | ВОТ: ЮО"
Altitude
Feet ENGINE: ULI-02 EXHAUST: na СА
250 2
5000 270 280 250
4000 290
2000 310 300
Sea Level 330 320 rie
Temp. °F 0°-20" | 20*-40° | 40*-
27
= мо._: Suggested main jet calibration is based on the use of
the Cuyuna exhaust system, “Unifilter” foam air filter and a Cuyuna
fuel pump. Changes of the above components will affect the fuel
E of the engine and therefore affect the carburetor calibra-
ION.
m NOTE: Main jet selection charts are to be used only as a
guideline. Cylinder head temperatures and firing end condition of
the spark plugs will determine actual main jet selection.
Needle Jet and Jet Needle:
In the VM-type carburetor, the needle jet and jet needle serve to
control the proper fuel/air mixture ratio during the so-called
medium throttle valve opening (between la and 34 opening). The jet
needle is tapered at one end and the ciearance between the jet nee-
die and the needle jet increases as the throttle valve opening gets
wider. The fuel/alr mixture ratio Is controlled by the height a the
“E ring that is inserted into one of the five slots provided in the
headof the Jet needie, see Figure 17. When the “E” ring is installed
in the number one slot it will provide the leanest setting possible for
the particular Needle Jet - Jet Needle combination installed. Posi-
tioning the “E" ring in the number five slot will provide the richest
setting. The variation of fuel flow based on the height of the “E"
ring is shown In Figure 18 When positioning the "E" ring, points to
be checked are:
1. Smooth and steady acceleration (% to % throttle).
2. Steady operation at constant throttle openings.
3, CHTs within limit.
LEAN
—e — |
—— 2
— 3
— 4
RICH че
FIG 17
28
FUEL FLOW [LAT
Ex 50% 15% 100%
THEETTLE YALYE OPENING
FIG 18
Pilot Jet and Pilot Air Screw (VM-type):
The fuel/air mixture ratio for the VM-type Mikuni carburetor is
regulated by the pilot jet and the pilot air screw. The normal pilot air
screw setting is from 1 - 1 3/4 turns out. For adjustment purposes
start with the pilot air screw 1 1/2 turns out. To determine the fully
closed position of the pilot air screw turn the screw clockwise until
it is hs de me
so UE uE ve я the pilot air sére a Me
= © ed TION © Eis ho a nig Wis ho
EEN apte = KP
a a lait ai Fh woriver 0 ig bmn helio if Le Y
To adjust the soi alr screw tu the idle ais screw so that the
engine APM |s increased to 10 - 20% above the targeted idle speed
see "Operating Limitations"). Turn the pilot air screw left and right
n % and % turn increments to find the setting which will produce
the greatest engine RPM. When you have achieved the greatest
engine RPM with the pilot air screw, back out the idle stop screw to
the eo engine idie RPM. Again using the pilot air screw, turn
left right in % to % turn increments to find the setting which
will produce the greatest engine RPM. The idle stop screw may
have to be re-adjusted e the idle RPM. If there is a certain range
where the greatest angine RPM can be obtained, (for instance, the
engine RPM does not € ange between 1% to 2 turns open) it would
be better for acceleration to select the pilot air screw setting of 2
turns open.
29
If the piiut air screw must be opened more than 2 turns, the pilot jet
15 too large (rich). If the pilot air screw must be less than 1 turn the
pilot jet is too small (lean).
E NOTE: Pilot air screw opening uu than 2 turns will cause
the spring to become ineffective. This could cause the pilot air
screw to come out during operation.
Pilot Jet and Pilot Mixture Screw (BV-type):
The fuel/air mixture ratio for the BV-type Mikuni carburetor is
regulated by the pilot jet and the pilot air jet. The flow of the fuel/air
mixture is regulated by the pilot mixture screw. The normal pilot
mixture screw setting is from 1 to 1 1/4 turns out. For adjustment
purposes start with the pilot mixture screw at a setting of | turn out.
To determine the fully closed position of the pilot mixture screw,
turn the screw clockwise until it is lightly seated. (Figure 19)
TOP VIEW
CHORE CABLE AMUSTHEKT
Г
4
E,
-- PILOT MIXTURE SCREW
E
TAMOTTLE CABLE ADFUSTMENT
)
To adjust the pilot mixture screw, turn the idle stop screw so the
engine RPM is increased to 10 - 20% above the targeted idle speed
(see "Operating Limitations”). Turn the pilot mixture screw left and
right in "4 to Y turn increments to find the setting which will pro-
duce the greatest engine RPM. When you have achieved the
greatest engine RPM with the pilot mixture screw, back out the
throttle stop screw to the targeted engine idle RPM. Again, using
the pilot mixture screw turn left and right in % to %2 turn increments
to find the setting which will produce the greatest engine RPM. The
throttle stop screw may have to be adjusted again. If there is a cer-
tain range at which the opening of the pilot mixture screw, when the
greatest engine RPM can be obtained (for instance, the engine RPM
does not change in the range of 1%: to 2 turns open) it would be bet-
ter for acceleration fo select the pilot mixture screw setting of 11%
turns.
If the pilot mixture screw must be opened more than 2 turns, the
pilot jet is too small (lean). If the pilot mixture screw must be less
than 1 turn the pilot jet is too large (rich).
E NOTE: Pilot mixture screw openings greater than 2 turns will
cause the spring to become ineffective. This could cause the pilot
mixture screw to come out during engine operation.
Ш NOTE: Refer to Cuyuna Service Manual for specific instructions
pertaining to jet changes and carburetor overhaul.
FUEL PUMP INSTALLATION
Theory of Operation: (Figure 20)
One side of the fuel pump is activated by crankcase pulses. As the
engine piston moves upward in the cylinder it creates a vacuum
which is transmitted via the impulse hose to the impulse diaphragm
(item 6).
The impulse diaphragm is flexed into the impulse chamber (item 5)
and the inlet check valve (item 3) is drawn open and fuel flows into
the fuel chamber {item 8) through the fuel inlet. As the piston moves
downward in the cylinder, it creates pressure, (primary compras-
sion), the Impulse diaphragm is flexed into the fuel chamber (item
B), the outlet check valve (item 4) is forced open and the inlet check
valve is closed. The pressure increases within the fuel chamber
which forces fuel out the outlet check valve and fuel outlet.
3
(7
KEY
1. FUEL OUTLET 2 [IMPULSE CHAMBER
2. FUEL INLET 6 DIAPHRAGM
3. INLET CHECK VALVE 7 IMPULSE FITTING
8
4. OUTLET CHECK VALVE FUEL CHAMBER
FIG 20
Installations:
The impulse-type fuel pump must be installed so that the Impulse
fitting of the fuel pump is higher than the impulse nipple of the
engine. If the fuel pump is mounted below the impulse nipple of the
engine, the fuel mixture will accumulate in the impulse chamber
stopping the pump action. The impulse line should be kept as short
as possible (6 inches or less).
High quality, tight fitting, fuel and impulse lines must be used, for
satisfactory performance of the fuel supply system. The fuel pump
must be isolated from engine vibration.
IGNITION SYSTEM
Capacitor Discharge Ignition Principles:
To produce and control the necessary voltage required for ignition,
a number of electrical components are used In conjunction with
each other. These components are:
1. Flywheel-Mounted Permanent Magnets - The flywheel-mounted
pe magnets provide a moving magnetic field when the
lywheel is rotating around the coils.
2. Exciting Coil - Mounted on the stator plate, just below the
pulser coll, is the exciting coil. One lead of the exciting coll is
grounded to the engine through the coil mount screws, the
other lead Is connected to the CDI amplifier.
32
ET а Ня ЕАК
3. Pulser Coil - Mounted on the stator plate just above the exciting
coil is the pulser. One lead of the pulser coil is attached to the
same red lead as the exciter coil. The other lead is connected to
the CDI amplifier.
4. CDI Unit - Mounted on the fan housing, contains a rectifier,
capacitor and a solid state switch.
5. Ignition Goil - An ignition coil mounted on the fan housing with
a high tension lead going to sach spark plug.
e - je
Немо
WHEN LA — 1
MAGNET
FIG 21
As the flywheel rotates, an altemnating current is produced in the ex-
citing coil. Because the CD Ignition system cannot utilize alter-
nating current, the current produced from the exciter coil is routed
through à rectifier in the CDI unit which eliminates the negative
flow. (Figure 21) The positive flow passes through the rectifier and
is sto In the capacitor of the CDI unit. Connected to this circuit
is a SCR switch. When the SCR is open, the exciter coil builds up a
charge in the capacitor. To fire the spark plug, the SCR switch is
closed or triggered by a pulse from the pulser coll. (The position of
the pulser coil in relation to the flywheel and the piston, triggers the
SCR at the precise moment to ensure the most efficient combus-
tion.) When the SCR switch is closed the capacitor discharges into
the primary winding of the external ignition coil. When the current
flow into the primary coil is at its peak the SCR switch is again
opened and a current is induced into the secondary winding of the
external ignition coil. The secondary winding of the external igni-
tion coil has many turns of fine wire in relation to the relatively few
turns of wire in the primary winding. This increases the voltage
delivered to the spark plug.
The timing of the ignition spark, is accomplished by a trigger im-
pulse from the pulser coil to the SCR switch of the CDI un: The
33
|
SCR switch requires a certain voltage to actuate it. At cranking
speeds and low RPM there is enough voltage when the piston is a
few degrees before top dead center (B.T.D.C.) to actuate the SCR
switch. As the engine RPM increases, the pulser coil has sufficient
voltage to actuate the SCR switch in an advanced position. Advanc-
ing the timing by electronic means insures easy starting and max-
imum efficiency at high REM.
The most important advantages of the CDI are: stronger ignition at
cranking speeds, no maintenance required of breaker points and
simpler adjustment of timing. These result in easier starting, peak
performance and low maintenance.
Ш NOTE: Refer to the Cuyuna Service Manual for specific
maintenance instructions of the ignitions system.
Another component that functions in the ignition system, but is not
mounted on the engine, includes the ignition switch.
IGNITION SWITCH INSTALLATION
The Nippendenso CD ignition system is a normally closed system.
The engine kill switch must be installed so that it will complete a
circuit between the YELLOW wire with a BLACK STRIPE, of the
stator plate wire bundle, and back to an engine ground. The circuit
must be complete for the engine to run and open to stop engine.
LIGHTING SYSTEM DIAGRAMS
The a diagrams apply to Cuyuna 430, 215 and ULII-02
models.
Diagram Number 1 denotes the circultry involved to wiring an elec-
trical load requiring only voltage regulation (12 VAC).
Diagram Number 2 denotes the circuitry involved to wire an elec-
eal load requiring voltage regulation and current rectification (12
VDC).
Ш NOTE: Lighting diagrams are located in the back of this
manual.
FAN BELT TENSIONING
The proper belt deflection should be 1/8" on either side. Proper ad-
justment is made by adding or removing shims between the upper
pulley sheaves. See your Cuyuna service manual for instructions.
AIR FILTER MAINTENANCE
Air filtars may be cleaned by flushing the filter in a cleaning solvent.
Wring dry.
= = т гл E = = = TEE = E т = = т. = 7 mu En e — 2 ren Fa г. E per = т Fp pen
3 AUTION © Ne ser ui y engine without an ait Mi ter.
et E RI oe ae AR Ь
PERIODIC MAINTENANCE SCHEDULE
Hours
Spark Plug Inspection 10
Spark Plug Replacement 50
Fan Drive Belt Adjustment - after first 5 hours then every 25
Ignition System Adjustment 50
Fuel Filter Replacement 50
De-Carbon Cylinder Head
Piston Dome 100
Exhaust Port 100
Air Filter Replacement As Needed
B NOTE: Refer to the Cuyuna Service Manual for specific instruc-
tions pertaining to de-carbonizing engine parts.
PREPARATION FOR STORAGE
Prior to storing the Cuyuna engine for any length of time, it must be
properly serviced to prevent rusting of internal components. To
prepare the engine for storage, use the following procedures:
1. Drain all fuel from the fuel tank, Disconnect the fuel line from
the fuel pump inlet fitting.
2. Remove the air filter from the carburetor.
3. Start the engine and allow it to idle. Rapidly injec a good two-
cycle oil (petroleum based) into the carburetor for a period of 10
- 20 seconds until the engine stops. This procedure coats the
O and internal parts of the engine with a protective
iim of oil.
4. Wash the air cleaner in a cleaning solvent, Wring dry. Re-install
on carburetor.
5. If the engine is being used in the upright position, remove the
spark plugs. Pour 1 fl. ounce of a good two-cycle oil (petroleum
based) down each spark plug hole and slowly turn the engine
over, just two (2) revolutions.
6. Re-install the spark plugs.
7. Plug the exhaust cutlet to prevent anything from entering the
exhaust system.
RETURNING THE ENGINE TO SERVICE
Raturning the engine to service and correctly preparing it for
another season will assure many hours of trouble-free operation. To
prepare the engine for use, follow this procedure.
1. Inspect all fuel lines and replace any that Ripon ho e Sine
me SN
swollen or cracked, Re-connect fuel line to
pump.
р [ET DS
2. Inspect the in-line fuel filter and replace if necessary. Inspect -.
Ca
Log
a
fuel tank venting system and clean if needed. Fill fuel tank with
fresh fuel mixture. el Е
3. Remove the spark plugs and clean or replace if they appear off
fouled. Re-gap spark plugs as required. Torque spark plugs to
20 ft. Ibs.
35
5
4. Inspect spark plug leads and caps for wear and tightness.
Replace caps that appear to be worn or loose. e
5. Inspect the fan drive belt for tightness, cracks or fraying. Adjust
6. Remove cover from exhaust outlet.
1.
10.
11.
12.
13.
. Obstructed
or replace as required.
TROUBLE SHOOTING
Engine will not start or starts with difficulty:
Possible Cause
No fuel in fuel tank.
fuel line or
filter.
. Fuel tank vent obstructed.
. Inoperative or improperly
installed fuel pump.
. Ignition switch in “OFF”
position or faulty wiring.
Spark plugs Improperly
gapped, fouled or malfunc-
ioning.
. Water in fuel.
. Engine flooded.
. Enrichment valve not ON,
Throttle valve open.
Improper adjustment of
pilot air screw (VM-type) or
pilot mixture screw (BV-
type).
Head gasket blown or leak-
ing.
Air leak in crankcase or in-
let system.
14. No spark.
15. No compression (second-
ary).
1.
12.
13.
14.
15.
. See “Startin
. Ensure enrichment valve is
Remedy
Fill tank with fresh fuelloil
mixture (see “Fuel Require-
ments’).
. Check fuel lines and in-line
filter for obstructions.
Clear or replace.
. Check fuel tank vent for
obstruction, Clear vent.
. Gheck for proper operation
and installation (refer to
Cuyuna Service Manual).
. Turn ignition switch “ON”
ot check for faulty wiring
and repair as needed (see
“Ignition Switch Installa-
tion").
. Remove spark plugs, ad-
just, clean or install new
spark plugs.
. Drain and flush fuel tank
and lines. Refill with fresh
fuel/oil mixture (see “Fuel
Requirements”).
Procedures".
ON.
. Close throttle valve.
, See
“Carburetor Adjust-
ment”.
Replace gasket.
Check crankcase pressure
refer to Cuyuna Service
anual).
Check Un switch posi-
tion. If found to be “ON”
check all ignition wire con-
nections for being clean
and tight.
Hemove cylinder head and
inspect pistón, rings and
cylinder bore condition.
)
Engine will not idle or missing at low speed:
1.
2.
. Spark plugs
Possible Cause
Loss of comprassion or low
compression.
Carburetor improperly ad-
justed - (A) Idle speed too
low (B) Low speed system
out of adjustment.
. Dirty carburetor passages
or plugged jets.
improperiy
gapped, fouled or malfunc-
tioning.
. Improper fuel/oil mixture -
(A) Too much oil (B) Too
little oil.
. Head gaskets blown or
leaking.
. Air leak in crankcase or air
inlet.
1
Remedy
Worn piston, rings or cyl-
Inder (refer to Cuyuna Ser-
vice Manual).
. See “Operating Limita-
tions" (idle) and “Carbu-
retor Adjustment”.
. Check carburetor (refer to
Cuyuna Service Manual).
. Remove spark plugs, ad-
just, clean or install new
spark plugs.
. Refuel using proper fuel/oil
mixture.
. Replace gasket.
. Check crankcase pressure
(refer to Cuyuna Service
Manual).
No Acceleration - Idles well but will not take throttle (dies down):
4
5.
6
7.
a slow Acceleration -
gio ET
ele,
Fe а 1
Fa т 1 т
e
ft
ly.
E A £
mo al; "El
SE
Eo
J aa
a =
f= 8
mo 1
Possible Cause
. Pilot air screw (VM-type) or
pilot mixture screw (BV-
type) set too lean.
uel lavel set too low.
. Fuel pump not supplying
enough fuel due to: (A)
Punctured diaphragm (B)
Non- Y ao check
valve (C) Impulse line clog-
ed or leaking.
uel line obstructed.
Improper ignition timing.
. Air leak In crankcase inlet
system.
Spark plugs improperly
gapped, fouled or malfunc-
tioning.
Possible Cause
Spark plug Improperly
gapped, fouled or malfunc-
tioning.
Blown or leaking head
gasket.
1.
=~ oO Oh +
+.
. Clear
Remedy
See “Carburetor
ment”.
Adjust-
. Refer to Cuyuna Service
Manual.
. Replace fuel pump, clear or
replace impulse line.
obstruction or
replace.
. Refer to Cuyuna Service
Manual.
. Refer to Cuyuna Service
Manual.
. Remove spark plugs, ad-
just, clean or install new
spark plugs.
Low Top RPM - hard to start:
Remedy
Remove spark plugs, ad-
just, ciean or install new
Зо plugs.
place oad gasket.
3. Piston and cylinder scored.
4. Float adjustment too high.
5. Main Jet too rich.
6. Excessive propeller load-
ing.
. Refer to Cuyuna Service
Manual.
. Refer to Cuyuna Service
Manual.
See "Carburetor Adjust-
ment”.
. Reduce propeller loading.
о en = ©
Runs lean at all speeds - coughs, spits, slows down, surges:
Possible Causes
1. Air leak in fuel lines.
. Fuel line obstructed.
. In-line fuel filter plugged or
dirty.
. Fuel pump not Supe
enough fuel due to: (A) Ob-
structed impulse line (B)
Punctured diaphragm (©)
inoperative check valve.
. Carburetor inlet needle and
seat obstructed.
. Float level too low.
La CI
. Carburetor is dirty.
lean.
. Carburetor loose on flange.
. Rubber flange leaks.
. Air leak in crankcase or In-
let system.
5
6
7
8. Pilot Jet or Main Jet too
g
0
1
Engine missing under load:
Possible Cause
1. Spark plug improperly
¡pu fouled or maifunc-
tion
2. Heat range of spark plug
too cold.
HS 3 Engine improperly timed.
+
Broken spark plug con-
‘nactor.
8 WE per carburetor adjust-
t (LEAN) (RICH).
ag we propeller load-
tl dd
Remedy
, Check fuel lines and fit-
tings, correct as required.
. Clear or replace fuel line.
. Replace filter.
& OP +
. Clear impulse line or re-
place, replace fuel pump.
. Refer to Cuyuna Service
Manual.
. Refer to Cuyuna Service
Manual.
. Clean carburetor - refer to
Cuyuna Service Manual.
See “Carburetor Adjust-
ment”.
. Tighten
screw,
. Replace rubber Neg"
. Refer to Cuyuna Service
Manual.
rubber flange
+ 0 0 0 ~N © ©
Remedy
1. Remove spark plugs, ad-
just, clean or Install new
spark plugs.
2, See “Spark Plug" data.
3. Refer to Cuyuna Service
Manual.
4. Replace connector.
5 See "Carburetor
ment”.
6. Reduce load.
Adjust-
Engine overheats:
Possible Cause
1. Fuel line or filter ob-
structed.
2. Improper carburetor adjust-
ment.
3. Improper (too lean) fuel
mixture.
4. Fuel octane rating too low.
5. Alr leak in crankcase or in-
let system.
6. Engine improperly timed.
7. Loose fan drive belt.
B. Cooling fan clogged, en-
ine dirty.
9. Carbon buildup.
10. Excessive propeller load-
ing.
AR TENA ET EE D
Possible Cause
1. Excessive propeller load-
ing.
= 2. Piston seizure.
a
| 3. Main jet too rich.
E Possible Cause
E 1. Carburetor icing.
5 2. Piston seizure.
4 Weal or no spark:
ue 7 Possible Cause
© 1, Ignition switch “OFF”.
; E
LA a pee
de E
SA A
=
38
3. See
Remedy
1. Clear or replace fuel line,
replace fuel filter.
2 See "Carburetor Adjust-
ment”.
3. See "Fuel Requirements”.
4. See “Fuel Requirements”.
5. Refer to Cuyuna Service
Manual.
6. Refer to Cuyuna Service
Manual.
7. See “Fan Drive Belt Ten-
sioning”.
8. Clean engine.
9. De-carbonjze combustion
chamber, exhaust port,
piston dome.
10. Reduce propeller loading.
Engine loses power after take off (1-3 min.) or will not go back to full
power after throttle opening is reduced:
Remedy
1. Reduce propeller loading.
2. isa St through in-
take and exhaust ports. If
damaged replace parts as
required. Refer to Cuyuna
Service Manual.
“Carburetor
Adjust-
ment”.
Remedy
1. Avoid flying In known icing
conditions.
2. Inspect piston through in-
take and exhaust ports, If
damaged replace paris as i
required. Refer to Cuyuna
service Manual. MRE
R ly i E Fr i
1. Turn ignition “ON.
2.
3.
4.
Spark plugs Incorrectly
gapped, fouled or maifunc-
tioning.
Faulty wiring.
Faulty
ignition compo-
nents.
2.
3.
4.
Remove spark plug and ad-
just, clean or install new
spark plugs.
Check wiring for opens,
loose connections, etc.
Hepairs required.
Refer to Cuyuna Service
Manual.
Good spark, but engine runs on one cylinder:
E
hea GG MN
= CN
Possible Cause
Spark plug incorrectly
gapped, fouled or malfunc-
tioning.
. Broken spark plug con-
nector.
. Alr leak in crankcase or
intet system.
. Head gasket blown.
. Cylinder head leaking.
. Cracked cylinder wall.
. Low or no compression.
, Faulty ignition.
. Low or no primary com-
pression (crankcase pres-
sure).
E
2.
3
4,
5. Check heads for warps and
=| Of
.see Cuyuna
Remedy
Remove spark plug, adjust,
ny or install new spark
ug.
eplace spark plug con-
nector.
. Refer to Cuyuna Service
Manual.
Replace head gasket.
cracks, replace gaskets
and heads.
. Replace cylinder assembly,
. Worn rings,
piston or
cylinder.
Service
Manual for ignition system
troubleshooting.
. Pressure test engine. See
Cuyuna Service Manual for
instructions.
Engine runs on after switch is shut “OFF”:
1.
2.
3.
Possible Cause
Amar win
ark plug
high.
Carbon build-up.
heat range too
1.
2.
3.
Remedy
Check for shorts to ground.
See “Spark Plug Data”.
De-carbonize combustion
chamber, exhaust port and
piston dome.
Cranks over extremely easy on one or both cylinders - loss of com-
pression:
1.
2.
3.
4.
5.
Possible Cause
Lose spark plug.
Head bolts not tight.
Blown head gasket.
Excessive ring end gap.
Scored piston.
40
ón ACORN
Remedy
. Re-torque spark plug.
. Re-torque head bolts.
. Replace gasket.
. Check ring end 94 and
replace as requir
. Inspect piston through in-
take and exhaust port.
Replace faulty piston.
Refer to Cuyuna Service
Manual,
Rar pe fdr а
Faria ER TA AE
)
Engine won't crank over - Unable to rotate flywheel:
Possible Cause Remedy
1. Piston rings rusted to cyl- 1. Remove cylinder and
inder wall. piston and replace defec-
tive parts. Refer to Cuyuna
Service Manual.
2. Crankshaft seized to bear- 2. Replace crankshaft as-
ing (Main or Rod). sembly.
3. Connecting rod broken. 3. Replace crankshaft
assembly.
4. Flywheel seized to stator 4. Remove flywheel and re-
plate. place defective parts. Refer
to Cuyuna Service Manual.
5. Engine improperly as- 5. Recheck assembly pro-
sembied after repair. cedure,
6. Seized piston (overheated). 6. Remove cylinder and
repair.
7. Foreign material In crank- 7. Disassemble crankcase
case. and clean,
- Engine vibrates excessively or runs rough and smokes:
y Possible Cause Remedy
5 1. Pilot or Main system too 1. See “Carburetor Adjust-
Ae rich. ment”.
“2. Enrichening valve not fully 2. Check operation. Refer to
e closing. Cuyuna Service Manual.
2 3. Float level too high. 3. Refer to Cuyuna Service
au Manual.
= 4. Carburetor air passages 4. Refer to Cuyuna Service
E plugged. Manual.
w=. 9. Exhaust system ob- 5. Check and clear exhaust
de structed. system, |
,. 6. Water in fuel. 6. Drain fuel cell, fuel lines
and carburetor. Dry spark
plug firing end. Fill fuel cell
with fresh fuel mixture. See
“Fuel Requirements”.
& . 7. Engine mount bolts not 7. Check and re-torque engine
E... Secure. mount bolts.
i. 8. Propeller andfor propeller 8. Check propeller and pro-
à». drive system out of peller drive system for
balance. proper balance.
3 2 Engine won't start - kicks back and backfires:
с 2 Possible Causes Remedy
E 4 Flywheel key missing or 1. Replace key. se
о E 1 sheared. Fh hu
в Improper ignition timing. 2. Refer to Cuyuna Service
| Manual, ea .
ue 41
TORQUE SPECIFICATIONS
Torque Specification 215R/D 430R/D ULII-02
Cylinder Head Nuts 16 - 18 ft. Ibs.
Cylinder Base Nuts 16-18 ft. Ibs.
Intake Manifold Nuts 16-18 ft. Ibs.
Spark Plugs 20-22 ft. Ibs.
Fan Housing Screws
Fan Shaft Nut 20 - 22 ft. Ibs.
Impulse Fittings & Plug 50-60 in. Ibs.
Flywheel Nut 46 - 50 ft. Ibs.
All 6mm Screws 6 - 8 ft. Ibs.
All 5mm Screws 40-50in. Ibs.
16 - 18 ft. Ibs.
| TIGHTENING SEQUENCE
FOR CYLINDER HEAD NUTS
D
E D |
æ 5
ad La = @ = Е =
TIGHTENING SEQUENCE FOR CYLINDER BASE NUTS |
D D DD ®
PTO SIDE
E @ © &
42
DEEE EE AS
oie ll Bed EN fe a LE mn a оо -
pa РОТА fr Sr dE hr 2 e "a ancla
" La a
A Er
Mee
PE A
cd ai
a RE к,
Fo =r
HER
Te
hs
"A
GENUINE REPLACEMENT PARTS
When replacement of parts is necessary, use only genuine Cuyuna
pacts. They are precision made to insure high quality and correct fit.
efer to the Cuyuna illustrated parts book for the correct part
number, quantity and description,
Service parts should be purchased through the dealer from which
you purchased the product containing the Cuyuna engine. Provide
your dealer with full details of your engine, including the serial
Ra model number and the product in which your engine is
nstalled.
CUYUNA ACCESSORIES AND PUBLICATIONS
Part Number
Cure e 000-44-001-000
Sold in case lots (24-16 oz. cans)
co a rt 002-53-027-000
Regulate alternator output to 17 volts AC
ue REINA 002-53-024-000
a Regulates alternator output to 12 volts DC
& Electric Starter (R model-twin).................... 291-31-910-000
be. 10 |bs., ring gear mounts on PTO shaft
E. HiFPerformance Kit (4300nly) ..........._...e ms... 430-31-365-000
Be Rated 43 h.p. at 6800 RPM (std)
© Dual Carburetor Kit (430 only) ...............—..—.. 430-31-367-000
i Mo be used with Cuyuna exhaust system for 43 h.p. at 6800
e
ES “Flow-Thru” Cylinder Head . ..................... 438-07-016-000
id improves airflow and better balance of cylinder temperature
© Carburetion and Exhaust Systems. ........... Specify application
be Ru Jy series carburetor and Cuyuna when ordering
exhaust.
E: Cuyuna Engine Service Manual (NEW 1983)
= A revised comprehensive manual covering engine and car-
SEE buretor - disassembly, Inspection, reassembly and operating
6 procedures.
Cuyuna lllustrated Parts Manual
+ Exploded view of engine parts and their respective numbers.
+ Guyuna Engine Theory Manual
= = Detailed examination of the design, function and operation of
me . engines manufactured by Cuyuna.
= Cuyuna Fuel System Theory Manual
=. Detailed examination of the design, function and operation of
E... carburetors used on the Cuyuna engine.
~~ Luyuna Electrical Systems Theory Manual
= Detailed examination of the design, function and operation of
the electrical systems used on Cuyuna engines.
e"
La
e EA
ak Te hr ny
wu 4 is y=
Plat ar
= В: phare
CAT тая
Rey we om mmm Ba
Sv
Ce
Nan pre
m „=
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or ar
E
CONTROL
Box NOTES!
TACH MOVEMENT I ЧО - LER
Y CABLES
“12 MENTE fey) BLACK,
ento a | STARTER
COIL —— Sd | TCH
= В БЕН : NORMALLY
у y “OPEN
== 900 — — — на
Ш BLUE LET ı
| a i
TAGE SA CLECTRIL START y DEF -0N SWITCH i
Bia | | Y A
iarr-onnl_ | :
| =
KILL
WITCH
YELLOW
CIRCUIT
MAME
ten
E a CE a |
+ CABLE
I
!
I
|
= BATTERY
Po STARTER
A | LI7V SZ AMP HOUR er
a | BLACK x = =
ы i — —
i | TRIGGER BATTERY в EABLE =
- >| cel u EGULATOR MECTIFIER NED
3 | E al GROUND TD CHASSIS весы
1 |
| -
| 12 VDC
| ENGINE 430 - ULI-02 C.D. Ignition with Electric Start
| LIGHTING {OIL DIAGRAM 2
м ны стон нс сн
gn ey I ee AT в
EEE ENTE DATAN
a E ï
E
Hee pa
Na e y
SC YELLOW
E
er La
E
и ré =r © = 2)
were к: us Eta =
BLACK/RED
BLACK
=
|
connreren
tr eu
12 VAC DIAGRAM 1
215 - 430 - ULN-02 C.D. Ignition
=
|
FELLOW BLACH
In] ORANGE
в TACH
5 ere wn MOVEMENT
Z| ORANG
VOLTAGE REG CONNECTOR =] ape
Mm
GEN, COIL
TRIGGER CONIL
ENGINE
a ROUND
— | Fable —
"ECT
GROUND TH CHASSIS
BLACK WHITE
BLACK
VOLTAGE REGULATOR
SIHK RE: BRACKET
IGNITION “COI
y LTA i)
= | SWITCH |
BLUE Ё
5 E | LIGHTS |
MILL y pm
' [SWITCH i :
me = I |
= CONNECTOR
y
YELLOW/ BLACK
ELA TEE
BLACK WHITE
BLACK
CONTROL
BOX
CHASSIS GROUNG Y HEAT
ENGINE LOG
| Total | |
Time Description of Inspection
In Maintenance, Repairs
Date | Hours |
Service _ and Comments.
I
|
|
A Th Fi ="!
ROLE
46 ET en A rer A
Date
Total
Time
In
Service
Y
ENGINE LOG
y
Description of Inspection
Maintenance, Repairs
and Comments.
Te
47