Onan CCKB User manual

Onon
Operators
Manual
Engines
927-0151
SPEC J
9-85
Printed In U SA

Safety Precautions
It is recommended that you read your engine manual and
become thoroughiy acquainted with your equipment be¬
fore you start the engine.
This symbol If used warns of imme¬
diate hazards which will result In
severe personal Injury or death.
This symbol refers to a hazard or
unsafe practice which can result In
severe persona/ Injury or death.
Fuel System
• DO NOT fill fuel tanks while engine is running.
• DO NOT smoke or use an open flame in the vicinity of
the engine or fuel tank. Internal combustion engine
fuels are highly flammable.
• Fuel lines must be of steel piping, adequately secured,
and free from leaks. Piping at the engine should be
approved flexible line. Do not use copper piping for
flexible lines as copper will work harden and become
brittle enough to break.
• Be sure all fuel supplies have a positive shutoff valve.
ADANGER
AWARNING
ACAUTION
This symbol refers to a hazard or
unsafe practice which can result In
persona/ Injury or product or properly damage.
Fuels, electrical equipment, batteries, exhaust gases and
moving parts present potential hazards that can result in
serious, personal Injury. Take care in following these
recommended procedures.
Safety Codes
• All local, state and federal codes should be consulted
and complied with.
• This engine is not designed or intended for use in
aircraft. Any such use is at the owner's sole risk.
General
Exhaust System
• Exhaust products of any internal combustion engine
are toxic and can cause injury, or death if inhaled. Alt
engine applications, especially those within a confined
area, should be equipped with an exhaust system to
discharge gases to the outside atmosphere.
• Do not use exhaust gases to heat a compartment.
• Make sure that your exhaust system is free of leaks.
Ensure that exhaust manifolds are secure and are not
warped by bolts unevenly torqued.
Exhaust Gas is Deadly!
Exhaust gases contain carbon monoxide, a poisonous gas
that can cause unconsciousness and death. It is an odorless
and colorless gas formed during combustion of hydro¬
carbon fuels. Symptoms of carbon monoxide poisoning
are;
• Provide appropriate fire extinguishers and install them
in convenient locations. Use an extinguisher rated ABC
byNFPA.
• Dizziness
• Headache
• Weakness and Sleepiness
• Vomiting
• Muscular Twitching
• Throbbing in Temples
• Make sure that all fasteners on the engine are secure
and accurately torqued. Keep guards in position over
fans, driving belts, etc.
Ifyou experience any of these symptoms, get out into fresh
air immediately, shut down the unit and do not use until it
has been inspected.
• If it is necessary to make adjustments while the engine is
running, use extreme caution when close to hot ex¬
hausts, moving parts, etc.
Protect Against Moving Parts
• Do not wear loose clothing in the vicinity of moving
parts, such as PTO shafts, flywheels, blowers, coup¬
lings, fans, belts, etc.
• Keep your hands away from moving parts.
Batteries
• Before starting work on the engine, disconnect batter¬
ies to prevent inadvertent starting of the engine.
• DO NOT SMOKE while servicing batteries. Lead acid
batteries giveoff a highly explosive hydrogen gas which
can be ignited by flame, electrical arcing or by smoking.
• Verity battery polarity before connecting battery cables.
Connect negative cable last.
The best protection against carbon monoxide inhalation is
proper installation and regular, frequent inspections of the
complete exhaust system. If you notice a change in the
sound or appearance of exhaust system, shut the unit down
immediately and have it inspected and repaired at once by a
competent mechanic.
Cooling System
• Coolants under pressure have a higher boiling point
than water. DO NOT open a radiator pressure cap when
coolant temperature is above 212®F (100®C) or while
engine is running.
Keep the Unit and Surrounding Area Clean
• Make sure that oily rags are not left on or near the
engine.
• Remove all unnecessary grease and oil from the unit.
Accumulated grease and oil can cause overheating and
subsequent engine damage and present a potential fire
hazard.
E-S

Table of Contents
TITLE PAGE
INTRODUCTION . 2
Engine Set-Up . 3
Operation . 4
Maintenance . 6
Periodic Maintenance Scheduie . 9
Adjustments . 10
AWARNING
INCORRECT SERVICE OR REPLACEMENT OF PARTS CAN RESULT IN SEVERE
PERSONAL INJURY AND/OR EQUIPMENT DAMAGE. SERVICE PERSONNEL
MUST BE QUALIFIED TO PERFORM ELECTRICAL AND/OR MECHANICAL
SERVICE.
1

Introduction
KNOW YOUR ENGINE
Read this manual carefully, observing all WARNINGS
and CAUTIONS. Operating instructions, adjustments
and periodic maintenance procedures are given so
you ... the owner, can keep your unit running like new
and expect many years of dependable service from it.
Remember... any machine, regardless of design or
type, will perform only in relation to the service it
receives. Regularly scheduled maintenance lowers
operating costs.
ENGINE MODEL REFERENCE
Identify your model by referring to the MODEL and SPEC
(specification) NO. as shown on the unit nameplate.
Always use this number and the engine serial number
when making reference to your engine.
If a major repair or an overhaul is necessary. Onan
recommends that a competent mechanic either do the
job or supervise and check the work of the mechanic
assigned to do the job to ensure that all dimensions,
clearances and torque values are within the specified
tolerances.
An engine service manual and complete parts catalog
are available at additional cost. Contact your nearest
authorized dealer or Onan Parts and Service Center.
REFERENCE MANUALS
Parts Catalog . 927-0404
Major Service Manual . 927-0754
These instructions conisin the SI metric equivalents following
immediately in parentheses after the U.S. customary units of measure.
SPECIFICATIONS
Engine Design .Opposed two cylinder,
four cycle, and aii cooled
Bore. 3.25 inch (82.55 mm)
Stroke . 3.0 inch (76.2 mm)
Displacement . 50 CiD (816 cm^)
Horsepower (3900 RPM) .20 BHP (14.9 kW)
Oil Capacity . 3.5 qt (3.3 litre)
Oil Capacity with filter change . 4.0 qt (3.8 litre)
Compression Ratio . 7.0 to 1
TUNE-UP SPECIFICATIONS
Spark Plug Gap - Gasoline . 0.025 inch (0.635 mm)
Spark Plug Gap - Gas . 0.018 inch (0.457 mm)
Breaker Point Gap . 0.020 inch (0.51 mm)
Valve Lash
Intake. 0.007 inch (0.18 mm)
Exhaust . 0.016 inch (0.41 mm)
Ignition Timing:
Standard Electric Start
(Stopped or Running) . 20®BTC
Manual Start with Spark Advance ... 1 “ATDC (Stopped)
24'’BTC (Running)
Electric Start with Magneto and
Spark Advance . S^BTC (Stopped)
24'’BTC (Running)
2

Engine Set-Up
Inspect the engine visually. Check for loose or missing
parts and any damage that may have occurred in
shipment.
Oil and fuel have been drained from
the engine prior to shipping from
Onan. Severe engine damage will result if engine is
started without oil.
ACAUTION
BATTERIES
The batteries and battery cables used for starting the
engine should be of sufficient size to provide prompt
starting. Undersized batteries will result in poor starter
operation and a very short starter service life.
AWARNINn Ignition of explosive battery gases
' cause severe personal iniury. Do
not smoke while servicing batteries.
CRANKCASE OIL RECOMMENDATIONS
Fill crankcase with correct amount of oil. Refer to
SPECIFICATIONS for crankcase capacity. Use oils
meeting the American Petroleum Institute (API) classi¬
fication SE or SE/CC.
Crankcase pressure can blow out hot
oil and cause serious burns. Do NOT
check oil while the engine is operating.
Do not overfill crankcase. Excess oil
causes higher operating fempera-
fures and may cause foaming.
lACAUTION
AWARNING
Oil Level
Check oil level at least every 8 hours of operation.
Check more frequently on a new or reconditioned
engine as oil consumption is higher until the piston rings
seat properly.
When adding oil between oil changes, it is preferable to
use the same brand, as various brands of oil may not be
compatible together. Refer to MAINTENANCE section
for recommended oil change intervals and procedures.
FUEL RECOMMENDATIONS
AVAMQwiMr'l Ignition of fuel can cause serious
a4WAnN»NO| persona/ injury or death by fire or
explosion. Do not permit any flame, cigarette, or other
igniter near the fuel system.
Use clean, fresh, unleaded gasoline. Regular leaded
gasoline may also be used but is not a preferred fuel. Do
not use highly leaded premium gasoline. Use of un¬
leaded gasoline results in less maintenance.
Do not use gasoline de-icers. Gaso¬
line de-icers can cause internal
damage to carburetor and fuel pump parts. Do not use
fuels containing alcohol concentrations greater than
ten percent. Fuel containing alcohol may cause poor
engine performance and internal engine
damage.
If regular leaded gasoline is used continually, carbon
and lead deposits should be removed from the cylinder
heads as required because of engine power loss.
Unleaded gasoline may be used safely after lead
deposits have been removed.
Spilled fuel can ignite and cause
serious personal injury or death.
Never fill the fuel tank when the engine is running.
AWARNING
ACAUTION
EXHAUST SYSTEM
Exhaust products of any internal combustion engine are
toxic and can cause injury, or death if inhaled. All engine
applications, especially those within a confined area,
should be equipped with an exhaust system to discharge
gases to the outside atmosphere.
AWARMiwr If^P^l^llof^ exhaust gases can
ibWAHNIIMLa jf, serious personal injury or
death. Use extreme care during installation to ensure a
tight exhaust system.
3

Operation
STARTING
Most engines are equipped with a start-stop switch and
cable controlled choke and throttle.
1. Place the throttle control in the SLOWposition and
the choke into the FULL choke position.
2. Turn the ignition switch on and engage starter. If
engine fails to start after 30 seconds determine the
cause. Wait one minute before recranking.
If the engine fails to start at first attempt, rust inhibitor oil used at
the factory may have fouled the plugs. Remove the plugs, clean
in a suitable solvent, dry thoroughly and reinstall. Heavy exhaust
smoke when the engine is initially started is normal and usually
caused by rust inhibitor oil..
3. When the engine starts, gradually push the choke
lever in until the engine runs smoothly.
4. Black smoke from the exhaust and a rough running
engine usually indicate over-choking.
5. To stop the engine, turn the ignition switch to the
OFF position.
BREAK-IN PROCEDURE
Controlled break-in is the ideal fitting of all internal
moving metal parts. Using the proper oil and applying a
conscientious maintenance program during this period
helps assure satisfactory service from your Onan engine.
Maintain the proper cooling and lubrication during
break-in. Run the engine at half load for the first three
hours with intermittent periods of full load to control
engine break-in.
' Aral iTinwl <^rong grade and weight of
iiUAU t lUiN ; engine operating
temperatures during break-in can cause engine
damage.
Check the oil level at least every five operating hours.
Add oil to keep it at the proper level, but never overfill as
overfilling may cause the oil to loam and enter the
breather system.
HOT WEATHER OPERATION
When operating the engine in temperatures above
100°F (38°C), pay particular attention to the following
items to prevent damage;
1. K eep the engine cooling fins clean and free of
obstruction.
A caution Pl^ 99 ^d or clogged cooling fins
__ can cause over/ieaf/ng and
engine damage.
AWARNtwr Contact with rotating machinery
44VvAnrMirM^ can cause serious personal injury
or death. Stay clear of rotating components and
ensure that protective shields and guards are in
place and secured before operating machinery.
2. See that nothing obstructs air flow to and from the
engine.
3. Ensure that you are using the proper grade and
weight of oil for ambient temperatures. Check the oil
level each time you fill the fuel tank.
4. Check the battery water more frequently than every
50 hours which is recommended under normal
conditions. High temperatures cause faster evapo¬
ration.
5. Change crankcase oil and filter more frequently
than recommended under normal conditions.
COLD WEATHER OPERATION
When the engine is being used in temperatures below
32‘’F (O^C), check the following items closely:
1. Use the correct grade and weight of oil for the
temperature conditions. Change the oil only when
the engine is warm. If an unexpected temperature
drop occurs when the engine is filled with summer
oil, before starting the engine, move it to a warm
location until the oil will flow freely.
2. Use fresh fuel. Fill the fuel tank after each day's use
to protect against moisture condensation.
3. Keep the battery in a well-charged condition.
DUST AND DIRT
1. Keep unit clean. Keep cooling system clean.
2. Service air cleaner as frequently as required.
3. Change crankcase oil and filter more often than
recommended under normal conditions.
OUT-OF-SERVICE PROTECTION
1. Run the engine until it reaches normal operating
temperature.
2. Turn off the fuel supply and run the engine until it
stops.
3. Drain oil from oil base while the engine is still warm.
Refill with fresh crankcase oil and attach a tag
stating viscosity used.
4

4. Remove spark plugs. Pour 1 ounce (2 tablespoons
or 28 grams) of rust inhibitor or SAE #50 oil into the
cylinders. Crank the engine over a few times.
Reinstall spark plugs.
5. Service air cleaner as outlined in MAINTENANCE
section.
6. Clean governor linkage and protect by wrapping
with a clean cloth.
7. Plug exhaust outlet to prevent entrance of moisture,
dirt, bugs, etc.
6. Wipe entire unit. Coat rustable parts with a light film
of grease or oil.
9. Provide a suitable cover for the entire unit.
10. If battery equipped, disconnect and follow standard
battery storage procedure.
RETURNING UNIT TO SERVICE
1. Remove cover and all protective wrapping. Remove
plug from exhaust outlet.
2. Check tag on oil base and verify that oil viscosity is
still correct for existing ambient temperatures,
3. Clean and check battery. Measure specific gravity
(1.260 at 77°F [25''C]) and verify level to be at split
ring. If specific gravity is low. charge until correct
value is obtained. If the level is low, add distilled
water and charge until specific gravity is correct.
4. Check that fuel filter and fuel lines are secure, with
no leaks.
5. Check carburetor, adjust if necessary.
6. Connect battery.
7. Start Engine.
After engine has started, excessive blue smoke Is exhausted
until the rust Inhibitor has burned away.
AWARNING
EXHAUST GAS IS DEADLY!
Exhaust gases contain carbon monoxrde, a poisonous gas that can cause
unconsciousness and death. It is an odorless and colorless gas formed during
combustion of hydrocarbon fuels. Symptoms of carbon monoxide poisoning are:
e Dizziness • Vomiting
• Headache e Muscular Twitching
• Weakness and Sleepiness • Throbbing in Temples
It you experience any of these symptoms, get out into fresh air immediately, shut
down the unit and do not use until it has been inspected.
The best protection aga/nsf carbon monoxide inhalation is proper installation and
regular, frequent inspections of the complete exhaust system. If you notice a
change in the sound or appearance of exbausf sysfem, shut the unit down
immediately and have it inspected and repaired at once by a competent mechanic.
5

Maintenance
A VA/ARMiKjr I Accidental starting ot the engine can
^yvAhirMiNU cause severe personai injury or
death. Disconnect the battery cable when repairs are
made to the engine, controls panel, or associated
equipment.
DAILY CHECKS OR EVERY 8 HOURS
The operator should daily make a complete visual and
audible inspection of the engine. Check the following
before starting the engine for the first time each day:
1. Check all fuel lines and fittings for possible leakage.
2. Inspect exhaust system for possible leakage and
cracks. Locate leaks in muffler and piping while the
engine is operating. Repair all leaks immediately
after they are detected for personnel safety.
3. Inspect air cleaner system for leaks. Make certain
that all clamps and fittings are tight and free of
potential leaks.
4. Check crankcase oil level with the engine off. If oil
level is at or below "add" markon dipstick (Figure 1),
add sufficient oil of the proper viscosity as specified
in the ENGINE SET-UP section to bring oil level to
the full mark on the dipstick. Do not operate engine
with oil level below the "add" mark.
Allow a minimum ol 10 minulet for the oil to drain down before
checking. The beat time to check the oil it after an overnight
shut-down period.
CAP AND OIL
LCVCU ll'IUIOM 1 vn
KEEP OIL
AT THIS LEVEL_
I
NEVER OPERATE
ENGINE WITH OIL
act 1 r\/ri
FULL
MT4
^“LUW
ALWAYS REPLACE
CAP TIGHTLY. OR
OIL LEAKAGE MAY
OCCUR
FIGURE 1. CRANKCASE OIL FILL
OIL CHANGE
Change crankcase oil after the first 25 hours of
operation. Thereafter change crankcase oil every 50
hours on engines equipped with oil filter and every 25
hours on engines without oil filter. If operating in
extremely dusty, high ambient, or low ambient conditions
change oil more often.
Run engine until thoroughly warm before draining oil.
Stop the engine, place a pan under the drain outlet and
remove the oil drain plug or open the drain valve. After
the oil is completely drained, replace the drain plug or
close the drain valve. Refill with oil of the correct API
classification and appropriate SAE viscosity grade for
the temperature conditions (refer to ENGINE SET-UP
section).
AUUADMIMP! crankcase oil can cause burns if
AkWAnNinfj: spilled or splashed on skin. Keep
lingers and hands clear when removing the oil drain
plug and wear protective clothing.
Oil level should be to the "full" mark of the dipstick. Start
engine and run for a short time to check for oil leaks
around the drain plug.
OIL FILTER CHANGE
Replace oil filter (Figure 2) after the first 25 hours of
operation, and every 100 hours thereafter. If operating in
extremely dusty, high ambient, or low ambient conditions
change oil filter more often.
Spin off oil filter element and discard it. Thoroughly
clean filter mounting surface and install new element,
making sure new gasket is inserted in the element.
Apply a thin film of oil to the gasket. Spin element down
by hand until gasket just touches mounting pad and
then turn down an additional 1/4-1/2 turn. Do not
overtighten.
6

With oil in crankcase, start engine and check for leaks
around filter element. Retighten only as much as
necessary to eliminate leaks, but do not overtighten.
IGNITION
Spark Plugs
Check, and regap spark plugs every 100 hours of
operation (Figure 3). Replace spark plugs that show
signs of fouling or electrode erosion.
FIGURE 3. SPARK PLUG GAP
Breaker Points
Check breaker points every 100 hours. Replace points
and condenser every 200 operating hours. Replace
sooner if points are pitted or burned. See ADJUSTMENTS
section.
COOLING SYSTEM
Check and clean cooling fins and chaff screen at least
every 50 hours. Remove any dust, dirt or oil which may
have accumulated.
BATTERIES
Disconnect negative ground strap from the battery
before working on any part of the electrical system or
engine.
Disconnect positive terminals before charging batter¬
ies to avoid damaging alternator or regulator.
AWARNING fSnition of explosive battery gases
_ can cause severe personal injury. Do
not smoke while servicing batteries.
Cleaning Batteries
Keep the batteries clean by wiping them with a damp
cloth whenever dirt appears excessive.
If corrosion is present around the terminal connections,
remove battery cables and wash the terminals with an
ammonia solution or a solution consisting of 1 /4 pound
of baking soda added to 1 quart of water.
Be sure the vent plugs are tight to prevent cleaning
solution from entering the cells.
After cleaning, flush the outside of the battery, the
battery compartment, and surrounding areas with clear
water.
Keep the battery terminals clean and tight. After making
connections, coat the terminals with a light application
of petroleum jelly or non-conductive grease to retard
corrosion.
Checking Specific Gravity
Use a battery hydrometer to check the specific gravity of
the electrol^e in each battery cell.
Hold the hydrometer vertical and take the reading.
Correct the reading by adding four gravity points (0.004)
for every five degrees the electrolyte temperature is
above SO® F (27'’C) or subtracting four gravity points for
every five degrees below 60°F (27°C). A fully charged
battery will have a corrected specific gravity of 1.260.
Charge the battery if the reading is below 1.215.
Checking Electroiyte Levei
Check the level of the electrolyte (acid and water
solution) in the batteries at least every 50 hours of
operation.
Fill the battery cells to the bottom of the filler neck. If cells
are low on water, add distilled water and recharge. If one
cell is low, check case for leaks. Keep the battery case
clean and dry. An accumulation of moisture will lead to a
more rapid discharge and battery failure.
ACAUTION
Do not add water in freezing weather
unless the engine is to be run long
enough (two or three hours) to assure a thorough
mixing of water and electrolyte.
Storing Batteries
If the engine is to be stored for more than 30 days,
remove the batteries. With the electroiyte level at the
bottom of the split ring, charge the battery before storing
it. After every 30 days the battery is in storage, bring it
back up to full charge. To reduce self-discharge, store
the battery in as cool a place as possible so long as the
electrolyte does not freeze.
7

CRANKCASE BREATHER
This engine uses a crankcase breather valve for main¬
taining crankcase vacuum. If the crankcase becomes
pressurized as evidenced by oii ieaks at the seals, clean
valve in a suitable solvent. Check and clean valve
screens and baffle every 200 hours of operation. See
Figure 4.
BREATHER HOSE
HOSE CLAMP
CAP AND VALVE
■ O" RING
SCREEN
BREATHER
TUBE
SCREEN
CLAMP
AIR CLEANER
Cartridge Air Cleaner
Check and clean air cleaner element every 25 hours
(Figure 5). Clean by gently tapping element on a flat
surface. Replace the element every 200 hours. Clean or
replace more frequently In dusty operating conditions.
Air Cleaner Wrapper (Pre-Cleaner [if used])
Wash in water and detergent and squeeze dry like a
sponge (Figure 5). Allow to dry. then coat evenly with
two tablespoons (26 grams) of SAE 30 engine oil. Knead
into and wring excess oil from pre-cleaner. Reinstall
over cartridge.
Failure (o adequately writtg out exceea oil Irom the wrapper may
cauM drop In englrte horeepower due to an increaaed raelrtction ol
Inlet air.
AIR CLEANER
ELEMENT
FIGURE 4. CRANKCASE BREATHER
1 WASH
2. SQUEEZE DRY
3. COAT WITH OIL
4. INSTALL OVER PAPER ELEMENT
EXHAUST SYSTEM
Make regular visible and audible Inspections of the
exhaust system throughout the entire life of the engine.
Locate leaks In muffler and piping while the engine Is
operating. Repair all leaks immediately after they are
detected for personnel safety.
~A WARMiKin Inhalation of exhaust gases can result
AAWMMiNir'ttj serious personal Injury or death.
Inspect exhaust system audibly and xisually tor leaks
daily. Repair any leaks immediately.
FIGURE 5. AIR CLEANER ASSEMBLY
6

PERIODIC MAINTENANCE SCHEDULE
Follow a regular schedule of inspection and servicing,
based on operating hours (see Periodic Maintenance
Schedule). Keep an accurate logbook of maintenance,
servicing, and operating time. Use the factory recom¬
mended Periodic Maintenance Schedule (based on
favorable operating conditions) to serve as a guide to
get long and efficient engine life. Regular service
periods are recommended for normal service and
operating conditions. For continuous duty, extreme
temperature, etc., service more frequently. For infrequent
use, light duty, etc., service periods can be lengthened
accordingly. Neglecting routine maintenance can result
in engine failure or permanent damage.
Foranyabnormalities in operation, unusual noises from
the engine or accessories, loss of power, overheating,
etc., contact your nearest Onan Service Center.
PERIODIC MAINTENANCE SCHEDULE
1
AFTFR FACH CYCLE OF INDICATED HOURS
SERVICE THESE ITEMS
— --r
8
25
50
100
200
ln<(r^Art FnninR Canerallv
X’
1
- - ♦
ChAi^k Oil Level
X
.^ervlre Air Cleaner
X*
Chanqe Crankcase Oil (with Filter)
X3
X2
Channe Crankcase Oil (without Filter)
x»
X2
Check Battery Electrolyte Level
X
Clean Coolino Fins
x*
Renlacn Oil Filter
xs
X*
Check nr Renlace Soark PIUQS
X
Check Rreaker Points
X
Renlace Points and Condenser
X
Clean Breather Valve
X*
Rerrlace Air Cleaner Element
X*
Check Valve Clearance
X3
X*
Compression Check
X"
Clean Carbon and Lead Deposits (Cylinder Head)
X*.s
X' - Check for fuel leaks. With engine running, visually and audibly check exhaust system for leaks
X> - Perform more often when running under severe operating conditions.
X> - Initial break-in check only.
X‘ - For detailed maintenance, contact an
- For engines running on unleaded fuel
Onan Service Center or refer to the 927-0754 SERVICE MANUAL
this interval may be extended to 400 hours.
'AWARNING
Inhalation of exhaust gases can result
in serious personal injury or death.
Do NOT use the air cleaner or exhaust elbow as a
supporting step. Damage to these and connecting
parts might cause an exhaust leak.
9

Adjustments
CARBURETOR
The carburetor idle and main mixture screws were set
tor maximum efticiency at the factory and should
normally not be disturbed. If adjustments seem nec¬
essary, first be sure the ignition system is working
properly and is not the source of the problem.
If adjustment is needed, proceed as follows;
1. Turn both mixture screws (Figure 6) in until lightly
seated, then back the idle mixture screw out 1-1/2
turns and the main mixture screw out 2-3 turns.
Forcing tho mixturo adjustment
screws tight wiil damage the
needle and seat. Turn in only until light tension can
be felt.
3. Move the engine speed control to the slow position.
4. Pull the governor back so the THROTTLE stop
screw is against its stop. Continue to hold the
governor arm in this position while completing the
adjustments described in step 5.
ACAUTION
THROTTLE
STOP SCREW
IDLE FUEL
ADJUSTMENT
FUEL
INLET
CHOKE
CHOKE
PLATE
MAIN FUEL
ADJUSTMENT
GOVERNOR CUP
GOVERNOR
SHAFT YOKE
THROTTLE STOP SCREW
SPEED
GOVERNOR SPRING
THIS DISTANCE
DETERMINES SENSITIVITY
GOVERNOR
ARM AND SHAFT
SJJJ
FIGURE 7. GOVERNOR SPEED ADJUSTMENT
FIGURE 6. CARBURETOR ADJUSTMENTS
AWARNING
T-handled main adjustment
screws are locked in position
with a packing nut. This nut must be loosened
before adjustments are made and retightened
afterward. Failure to tighten the packing nut may
result in leaking fuel, creating a serious fire hazard.
5. T urn the IDLE adjustment screw, IN until engine
speed drops and then OUT until engine speed
drops again. Over a narrow range between these
two settings, engine speed will be at its maximum.
Set the idle adjustment screw about 1/6 turn
outward from the midpoint of this range.
2. Start the engine and allow it to warm up thoroughly
(at least 10 minutes).
Some equipment manufacturers may require higher
throttle stop speed and governor low speed rpm
settings. Refer to equipment manufacturer’s Opera¬
tor's Manual for the correct rpm settings.
6. C heck the main mixture adjustment by rapidly
accelerating the engine from idle to full. The engine
should accelerate evenly and without hesitation. If it
does not, turn the main adjustment screw out in 1 /8
turn increments until the engine accelerates
smoothly, but do not turn it out more than 1 /2 turn
beyond the original setting.
10

BREAKER POINTS
The timing is adjusted during initial engine assembly
and is fixed by the point gap adjustment. To maintain
maximum engine efficiency, change the breaker points
every 200 hours of operation.
Replacement and Adjustment
1. Remove spark plugs.
2. Remove breaker box cover. Rotate crankshaft clock¬
wise (facing flywheel) until points are fully open.
3. Remove two mounting screws (A) and pull point set
out of box just far enough so screw (B) can be
removed. See Figure 8. Replace points and con¬
denser set. Do not completely tighten mounting
screws (A).
4. Adjust point gap by rotating crankshaft clockwise
(facing flywheel) by hand until the points are fully
open. Set the point gap (using flat feeler gauge) at
0.020 inch (0.51 mm) by adjusting screw (C).
Make sur* gaug* it citan and fiaa ot any graata, oil or
dirt.
5- Tighten mounting screws (A) and recheck point
gap. Place one drop of oil on breaker point pivot.
TO ADVANCE OR RETARD
FIGURE S. SETTING POINT GAP
6. Replace breaker box cover, coil wire, spark plugs,
and spark plug cables.
Continuity Test
As a check for proper ignition timing a continuity test
may be performed:
1. Adjust breaker points.
2. Remove blower housing to expose timing marks on
top of gearcase cover and flywheel (Figure 9).
3. Rotate flywheel clockwise until timing mark is
aligned with the mark corresponding to timing
specifications.
4. Connect an ohmmeter or a continuity test lamp set
across the ignition breaker points. Touch one test
prod to the coil lead terminal (screw B Figure 9).
5. Touch the other test prod to a good ground on the
engine.
6. Turn crankshaft against rotation (counterclockwise)
until the points close. Then slowly turn the crankshaft
with rotation (clockwise).
7. The lamp should go out or continuity is lost just as
the points break, which is where ignition occurs. If
timing is early (advanced) the point gap is too large.
If timing is late (retarded) the point gap is too small.
Adjust point gap accordingly.
11

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ONAN
COOPER
INDUSTRIES
1400 73rd Avenue N.E.
Minneapolis, MN 55432 [phone]
Telex 29 0476 (U-S.)
Telex 29 0856 (outside U S.)
TWX 910 576-2833
Clable ONAN