ENGINE
SERVICE
MANUAL
®
OHVI® V-Twin Engine
MODELS:
GTH760/990/1000
GTV760/990/1000
AIR-COOLED ENGINES
FOREWORD
This manual has been written and published by GENERAC® POWER SYSTEMS, INC.
to aid our dealers’ mechanics, company service personnel and general consumers
when servicing the products described herein.
It is assumed that these personnel are familiar with the servicing procedures for
these products, or like or similar products, manufactured and marketed by GENERAC® POWER SYSTEMS, INC. It is also assumed that they have been trained in
the recommended servicing procedures for these products, which includes the use
of mechanics hand tools and any special tools that might be required.
Proper service and repair is important to the safe, economical and reliable operation
of the products described herein. The troubleshooting, testing, service and repair
procedures recommended by GENERAC® POWER SYSTEMS, INC. and described
in this manual are effective methods of performing such operations. Some of these
operations or procedures may require the use of specialized equipment. Such
equipment should be used when and as recommended.
We could not possibly know of and advise the service trade of all conceivable
procedures or methods by which a service might be performed, nor of any possible hazards and/or results of each procedure or method. We have not undertaken
any such wide evaluation. Therefore, anyone who uses a procedure or method
not recommended by the manufacturer must first satisfy himself that neither his
safety, nor the product’s safety, will be endangered by the service or operating
procedure selected.
All information, illustrations and specifications contained in this manual are based
on the latest product information available at the time of publication. However,
GENERAC® POWER SYSTEMS, INC. reserves the right to change, alter or otherwise
improve the product at any time without prior notice.
Some components or assemblies of the product described in this manual may not
be considered repairable. Disassembly, repair and reassembly of such components
may not be included in this manual.
The engines described herein may be used to power a wide variety of products.
Service and repair instructions relating to any such products are not covered in
this manual. For information pertaining to use of these engines with other products,
refer to any owner’s or service manuals pertaining to said products.
RULES FOR SAFE OPERATION
4-CYCLE ENGINE THEORY
TABLE OF CONTENTS
SECTION 1: GENERAL INFORMATION
SECTION 2: IGNITION
SECTION 3: CARBURETION AND FUEL SYSTEM
SECTION 4: GOVERNOR CONTROLS AND GOVERNOR
SECTION 5: CYLINDER HEAD AND VALVES
SECTION 6: ELECTRIC STARTER
SECTION 7: ALTERNATORS
SECTION 8: LUBRICATION SYSTEM
SECTION 9: ENGINE DISASSEMBLY
SECTION 10: CYLINDER AND CRANKCASE COVER
SECTION 11: CRANKSHAFT AND CAMSHAFT
1
2
3
4
5
6
7
8
9
10
11
SECTION 12: PISTON, RINGS AND CONNECTING ROD INSPECTION AND ASSEMBLY
SECTION 13: ENGINE ASSEMBLY
SECTION 14: SPECIFICATIONS
Generac Power Systems does not approve or authorize the use of these engines on All Terrain Vehicles (ATV’s), go-carts,
motorbikes, aircraft products, personal watercraft, or vehicles intended for use in competitive events. The use of this product
in any other than it’s intended application will void the warranty! Use of these engines in such applications could result in
property damage, serious injury (including paralysis), or even death.
12
13
14
ATTENTION!
1
RULES FOR SAFE OPERATION
If any portion of this manual is not understood, contact the nearest
Dealer for starting, operating and servicing procedures.
Throughout this publication, and on tags and decals affixed to the
equipment, DANGER, WARNING, CAUTION and NOTE blocks are
used to alert personnel to special instructions about a particular
operation that may be hazardous if performed incorrectly or carelessly. Observe them carefully. Their definitions are as follows:
INDICATES A HAZARDOUS SITUATION OR ACTION WHICH, IF NOT
AVOIDED, WILL RESULT IN DEATH OR SERIOUS INJURY.
Indicates a hazardous situation or action which, if not
avoided, could result in death or serious injury.
Indicates a hazardous situation or action which, if not
avoided, could result in minor or moderate injury.
NOTE:
Notes contain additional information important to a procedure and will be found within the regular text body of this
manual.
These safety warnings cannot eliminate the hazards that they
indicate. Common sense and strict compliance with the special
instructions while performing the action or service are essential to
preventing accidents.
Four commonly used safety symbols accompany the DANGER,
WARNING and CAUTION blocks. The type of information each
indicates is as follows:
This symbol points out important safety information that, if
not followed, could endanger personal safety and/or property
of others.
This symbol points out potential explosion hazard.
$
This symbol points out potential fire hazard.
!
This symbol points out potential electrical shock hazard.
+
The operator is responsible for proper and safe use of the equipment.
The manufacturer strongly recommends that the operator read this
Owner’s Manual and thoroughly understand all instructions before
using this equipment. The manufacturer also strongly recommends
instructing other users to properly start and operate the unit. This
prepares them if they need to operate the equipment in an emergency.
RULES FOR SAFE OPERATION
Study these RULES FOR SAFE OPERATION carefully before operating or servicing this equipment. Become familiar with the OWNER’S
MANUAL and with the engine. The engine can operate safely, efficiently and reliably only if it is properly operated and maintained.
Many accidents are caused by failing to follow simple and fundamental rules or precautions.
The manufacturer cannot anticipate every possible circumstance that
might involve a hazard. The warnings in this manual and on tags and
decals affixed to the equipment, are therefore, not all-inclusive. If
using a procedure, work method or operating technique the manufacturer does not specifically recommend, ensure that it is safe for
others. Also make sure the procedure, work method or operating
technique utilized does not render the engine to be unsafe.
DO NOT tamper with the engine governed speed.
High operating speeds are dangerous and increase
the risk of personal injury or damage to the equipment. Operating at low speeds with heavy load may
shorten the engine’s life.
BEFORE OPERATING
•Gasoline is highly FLAMMABLE and its vapors are EXPLOSIVE. Do
not permit smoking, open flames, sparks or heat in the area while
handling gasoline. Avoid spilling gasoline on a hot engine. Comply
with all of the laws regulating storage and handling of gasoline.
•Store gasoline and other fuels only in containers designed and
approved for the storage of such materials.
•Pressure can build up in the fuel tank. Loosen the fuel cap slowly
to relieve any pressure in the tank.
•Add gasoline and other fuels in a clean, well-ventilated area. Wipe
up any spilled gasoline immediately. If gasoline has been spilled,
let it dry completely before starting the engine.
•Do not overfill the fuel tank. Always allow room for fuel expansion.
If the tank is overfilled, the fuel can overflow onto a hot engine
and cause a FIRE or an EXPLOSION.
•Thoroughly inspect the engine for loose or damaged parts before
each use. Do not use the engine until adjustments or repairs are
made.
•Check the oil level in the engine before each use.
•Inspect the engine periodically. Repair or replace all damaged or
defective parts immediately.
•Inspect fuel system frequently for leaks or damage. Repair or
replace any damaged or leaking component immediately. Never
attempt to change, alter or modify the engine fuel system in any
way that might affect safety or compliance with applicable codes
and standards.
2
WHILE OPERATING
RULES FOR SAFE OPERATION
•This engine was designed and manufactured for specific applications. Do not attempt to modify the equipment or use it for any
application for which it was not designed.
• Engine exhaust gases contain DEADLY carbon monoxide gas. This
dangerous gas, if breathed in sufficient concentrations, can cause
unconsciousness or even death. Operate this equipment only in the
open air where adequate ventilation is available.
•Do not insert any object through the cooling slots of the engine.
This could damage the equipment or injure personnel.
• Do not operate the engine faster than the speed necessary to operate
the equipment. Do not run the engine at high speed when not operating
the equipment.
•This engine requires an adequate flow of cooling air for its continued
proper operation. Never operate the equipment inside any room or
enclosure where the free flow of cooling air into and out of the equipment might be obstructed. Without sufficient cooling air flow, the
engine quickly overheats, damaging the engine or nearby property.
•Do not smoke around the engine. Wipe up any fuel or oil spills
immediately. Never leave oily or fuel soaked rags around the engine.
Keep the area around the engine clean and free of debris.
•Keep hands, feet, clothing, etc., away from moving parts of this
engine.
•Never operate the engine (a) in the rain; (b) in any enclosed compartment; (c) if the engine speed changes; (d) if the engine sparks; (e)
if flame or smoke is observed while the engine is running.
•Never work on this engine or handle any electrical device while
standing in water, while barefoot, or while hands or feet are wet.
DANGEROUS ELECTRIC SHOCK will result.
•Allow muffler, engine cylinder and fins to cool before touching.
•Remove accumulated combustibles from muffler area and cylinder
area.
•Install and maintain in working order a spark arrester before using
equipment on forest covered, grass covered, brush covered unimproved land. The state of California requires this (Section 4442 of
the California Public Resources Code). Other states may have similar
laws. Federal laws apply on federal land.
SERVICE INFORMATION
Service on this engine within and after the warranty period can be performed by any authorized
service dealer. Service technicians are factory
trained and capable of handling all service needs.
When contacting an authorized service dealer
about parts and service, always supply the com-
plete model number and serial number of your
unit as given on its data plate decal. See the illustration below for the location of the decal.
The warranty for this engine is included in the
owner’s manual.
CALIFORNIA PROPOSITION 65 WARNING
Engine exhaust and some of its constituents are known
to the State of California to cause cancer, birth defects
and other reproductive harm.
CALIFORNIA PROPOSITION 65 WARNING
This product contains or emits chemicals known to the
State of California to cause cancer, birth defects and
other reproductive harm.
!
3
Running engines produce heat. Engine parts,
especially muffler, become extremely hot.
Severe thermal burns can occur on contact.
Combustible debris, such as leaves, grass,
brush, etc. can catch
fire.
4-CYCLE ENGINE THEORY
If the engine is to run properly, four (4) events must occur in the proper sequence and at the correct time. These events are (A) intake, (B)
compression, (C) ignition and power, and (D) exhaust.
(A)
INTAKE
The piston is travelling from top dead center (TDC) to bottom dead
center (BDC). The cam has opened the intake valve. The piston's
downward movement in the cylinder creates a partial vacuum in the
cylinder. Air at atmospheric pressure is drawn into the cylinder through
the carburetor and is mixed with fuel in the carburetor. The fuel-air
mixture flows through the open intake valve into the cylinder. When
the piston reaches BDC, the intake stroke is over.
By the time the piston reaches TDC , combustion is already in progress.
The intake and exhaust valves remain closed as the expanding gases
of combustion force the piston downward.
(C)
IGNITION AND POWER
(B)
COMPRESSION
As the piston reaches bottom dead center (BDC), both the intake and
exhaust valves are closed. As the piston moves upward toward TDC,
the fuel-air mixture becomes compressed. Just before the piston
reaches TDC, ignition occurs.
(D)
EXHAUST
The exhaust stroke begins when the piston has reached BDC and has
started its upward movement. The intake valve is closed. The exhaust
valve is open to let gases escape.
4
SECTION 1: GENERAL INFORMATION
MAINTENANCE SCHEDULE
Every 8
Hours
or Daily
Every 50
Hours or
Yearly
Every
100
Hours or
Yearly
Check Oil Level •
Change Oil Note 1 Note 1
Change Oil Filter Note 1 Note 1
Service Air Filter Note 2
Fuel Filter •
Replace or Clean
Spark Plug
Clean Spark
Arrestor Screen
Check Valve
Clearance
Note 3 Note 3
•
•
Note 1: Change oil and filter after first eight (8) hours of
operation and then every 100 hours thereafter. Change sooner
when operating under a heavy load or in a dusty or dirty
environment or in high ambient temperatures.
Note 2: Service more often when operating in dirty or dusty
conditions.
Note 3: Check valve clearance and adjust (if necessary) after
first 50 hours of operation and every 100 hours thereafter.
Every
500
Hours
or Yearly
LUBRICATION:
Oil has four purposes. It cools, cleans, seals and lubricates. During
normal operation, small particles of metal from the cylinder walls,
pistons, bearings and combustion deposits will gradually contaminate
the oil. Dust particles from the air also contaminate the oil forming an
abrasive mixture which can cause wear to all of the internal moving
parts of the engine, if the oil is not changed regularly. Fresh oil also
assists in cooling. Old oil gradually becomes thick and loses its cooling
ability as well as its lubricating qualities.
RECOMMENDED OIL TYPE:
Using the proper type and weight of oil in the crankcase is extremely
important. Check the oil before each use and change the oil regularly
(see Figures 1-1 through 1-5). Failure to use the correct oil, or using
dirty oil, can cause premature engine wear and failure.
Use only high quality detergent oil rated with an API service
classification SN or higher. Do NOT use oil designated "for diesel
engines only" (example: CD).
The recommended oil weights include the following:
•During summer months: SAE 30. An acceptable substitute is
SAE 10W-30. After first oil change, synthetic oil is acceptable.
•During winter months: SAE 5W-30 or synthetic 5W-30. DO NOT USE
SAE 10W-40.
After first oil change, synthetic oil is acceptable.
1
FUEL AND OIL RECOMMENDATIONS
GASOLINE:
We recommend the use of clean, fresh lead-free gasoline. A minimum
of 85 octane is recommended. The use of lead-free gasoline results
in fewer combustion deposits and longer valve life.
Note: Using a fuel additive such as STA-BIL® fuel stabilizer, or an
equivalent, will prevent gum deposits from forming in the engine’s
fuel system.
Note: Some fuels, called oxygenated or reformulated gasolines,
are gasolines blended with alcohols, ethers or ethanol. Excessive
amounts of these blends can damage the fuel system or cause
performance problems. Do not use gasoline which contains Methanol. Use gasoline with the lowest percentage of alcohol, ether or
ethanol—10% or less.
It is also recommended that gasoline be purchased in small quantities, not more than a 30 day supply. FRESH gasoline minimizes gum
deposits, and also will ensure fuel volatility tailored for the season in
which the engine will be operated.
CHANGE OIL:
See "Section 14: Specifications" for crankcase oil capacities. Use no
special additives. Make sure that the unit is level when filling with oil.
DO NOT OVERFILL.
IMPORTANT: DO NOT OVERFILL. Check and maintain oil level regularly. Change oil and filter after first eight (8) hours of operation.
Thereafter, change oil and filter every 100 hours of operation. Change
oil more often if engine is operated in dirty or dusty conditions or if
engine is operated under heavy loads or in high ambient air temperatures.
1-1
SECTION 1: GENERAL INFORMATION
FILL / CHECK
Figure 1-1. Oil Fill/Check Vertical Engine
CHANGE OIL FILTER:
Replace oil filter every 100 hours. Before installing new filter, lightly
oil filter gasket with fresh clean engine oil. Screw filter on by hand
until gasket contacts filter adapter. Tighten 3/4 to one full turn far ther
(Figure 1-5).
Start and run engine at idle for 30 seconds and stop engine. Recheck
oil level and add if required. Restart engine and check for oil leaks.
OIL CHECK
Figure 1-2. Oil Check Horizontal Engine
OIL FILL
Figure 1-3. Oil Fill Horizontal Engine
Remove oil drain plug and drain oil while engine is still warm, Figure
1-4. Change oil filter (Figure 1-5) and replace drain plug.
Remove dipstick or fill cap and fill slowly with new oil of proper
service classification and viscosity grade. Fill to full mark on dipstick.
When checking oil level, dipstick must be inserted all the way in for
accurate readings.
DRAIN
Figure 1-4. Oil Drain
FILTER
Figure 1-5. Oil Filter
CLEANING INTAKE SCREEN:
Grass particles, chaff or dirt can clog the air cooling system, especially after prolonged service in cutting dry grass or when operating in
extremely dusty or dirty conditions. Continued operation with a clogged
cooling system can cause severe overheating and possible engine
damage. Figure 1-6 shows the areas to be cleaned. This should be a
regular maintenance operation, or clean intake screen and oil cooler
fins after each use.
1-2
INTAKE
SCREEN
SECTION 1: GENERAL INFORMATION
The air cleaner on every engine brought in for a check up or repair
should be examined and serviced. If the air cleaner shows signs of
neglect, show it to the customer before cleaning. Instruct the customer
on proper care, to assure long engine life.
OIL
COOLER
FINS
Figure 1-6. Clean Intake Screen & Oil Cooler Fins
REPLACE SPARK PLUGS:
Replace spark plugs every 100 hours of operation or every season,
whichever occurs first. Replace spark plugs if electrodes are burned
away, or the porcelain is cracked. Set spark plug gap at 1.1 mm
(0.043") for all models. Torque spark plugs to 19.0 Nm (168 in. lbs.).
SET PLUG GAP AT 1.1mm
(0.043 inch)
Note: Replace air cleaner gaskets and mounting gaskets that are
worn or damaged, to prevent dirt and dust from entering engine
due to improper sealing. Replace bent air cleaner mounting
bracket if necessary.
SERVICE CANISTER AIR CLEANERS:
Clean the air filter element(s) with compressed air every 50 hours or
every season, whichever occurs first. Replace the air filter element(s)
every 500 hours or if damaged (see Figure 1-8).
Figure 1-8. Canister Air Cleaner Components
1
Figure 1-7. Setting Spark Plug Gap
Note: For proper spark plug replacement, refer to the owner’s
manual for the specific product.
AIR CLEANER MAINTENANCE:
WARNING: NEVER OPERATE ENGINE WITH AIR CLEANER
ASSEMBLY OR AIR CLEANER CARTRIDGE REMOVED. FIRE
*
MAY RESULT.
A properly serviced air cleaner protects internal par ts of the engine from
dirt and dust particles in the air. If air cleaner instructions are not carefully followed, dirt and dust which should be collected in the cleaner
will be drawn into the engine. These particles are highly abrasive and
will cause the piston rings and cylinder bore to wear quickly. As the
rings and cylinder bore become worn, these abrasive particles enter
the crankcase and contaminate the oil, forming an abrasive mixture
which will cause wear on all of the internal moving parts.
SERVICE DUAL ELEMENT AIR CLEANERS:
Remove and service foam pre-cleaner every 25 hours or every season,
whichever occurs first. Service cartridge every 50 hours or every
season, whichever occurs first (see Figure 1-9).
COVER
AIR FILTER
ELEMENT
FOAM PRE-CLEANER
Figure 1-9. Dual Element Air Cleaner Components
1-3
SECTION 1: GENERAL INFORMATION
Note: The air cleaner assemblies on some equipment may have
been supplied by the equipment manufacturer. See the equipment
manufacturer’s owner’s manual for service information specific
to that product.
TROUBLESHOOTING
Most complaints concerning engine operation can be classified as
one or a combination of the following:
1. Will not start
2. Hard starting
3. Lack of power
4. Runs rough
5. Vibration
6. Overheating
7. High oil consumption
Note: What appears to be an engine malfunction may be a fault
of the powered equipment rather than the engine. If equipment is
suspect, see equipment affecting engine operation.
SYSTEMATIC CHECK
If the engine will not start and the cause of malfunction is not readily
apparent, perform a systematic check in the following order:
CHECK IGNITION:
If spark does not occur look for:
•Shorted ignition/ground wire (see Page 2-1)
•Two closed diodes in ground wire harness (see Page 2-1)
•Incorrect ignition coil air gap (see Page 2-3)
•Ignition coil failure
•Weak flywheel magnet
CHECK IGNITION (ENGINE RUNNING):
If engine runs but misses during operation, a quick check to determine if ignition is or is not at fault can be made by installing a spark
tester (Generac P/N 0C5969) between the spark plug lead and each
spark plug, Figure 1-10. A spark miss will be readily apparent when
the engine is running. If spark is good but engine misses, check for
a fouled spark plug.
SPARK
PLUG
LEAD
TESTER
1. Fuel
2. Ignition
3. Compression
This check-up, performed in a systematic manner, can usually be
done in a matter of minutes. It is the quickest and surest method of
determining the cause of failure. The basic checkup procedure is the
same for all engine models, while any variation, by model, will be
shown under the subject heading.
CHECK FUEL:
The fuel pressure on LP and NG generator engines can be checked
using a pressure test kit for LP and NG systems.
For gasoline engines, check the following:
1. Are the tanks full?
2. Is the fuel stale?
3. Is the tank vent open?
4. Is the fuel shutoff valve open?
5. Is the fuel pump working?
6. Is the fuel solenoid working?
SPARK PLUG
Figure 1-10. Running Check
CHECK IGNITION (FOULED PLUG OR OTHER CAUSES):
To check for a fouled spark plug or a non-functioning cylinder, attach
the spark tester (Generac P/N 0C5969) between the spark plug lead
and each spark plug. Start and run engine at top no load speed. Now
ground one spark plug, Figure 1-11. The engine should continue to
run on the other cylinder. Repeat this test with the other cylinder. If
the engine will not continue to run when making this test, the cylinder that is NOT grounded is not functioning and/or the spark plug is
fouled. Install a new spark plug before proceeding. If miss continues,
problem may be carburetion or compression. See Check Fuel, Check
Compression, and Cylinder Balance Test.
1-4
Figure 1-11. Checking For Fouled Plugs
CYLINDER BALANCE TEST:
If the engine is hard starting, runs rough, misses or lacks power,
perform a cylinder balance test to determine whether both cylinders
are operating to their full potential.
Tools Required:
SECTION 1: GENERAL INFORMATION
CHECK COMPRESSION:
It has been determined through testing that a simple and accurate
indication of compression can be made as follows:
Remove both spark plugs and insert a compression gauge into either
cylinder (one cylinder at a time). Open the throttle to Wide Open Throttle
(WOT) position. Turn engine over with engine starter until there is no
further increase in pressure. Record this reading. Repeat procedure
on other cylinder and record that reading. The difference between both
cylinders should not exceed 25%. More than 25% indicates loss of
compression in the cylinder with lower pressure. See example.
EXAMPLE:
Cyl. #1 Cyl. #2 Diff.
Eng. #1 165 PSI 160 PSI 5 PSI
Eng. #2 175 PSI 155 PSI 20 PSI
If compression is poor, look for:
Insufficientvalveclearance • Warpedcylinderhead
•
•Loosecylinderheadbolts • Warpedvalvestems
•Blownheadgasket • Wornboreand/orrings
• Burned valves, valve seats
and/or loose valve seats
1
1. Two Ignition Testers (Generac P/N 0C5969)
Attach an ignition tester between the spark plug lead and each spark
plug, Figure 1-10.
Start and run engine at top no load speed and note spark at ignition
testers. If the spark is equal at both ignition testers, the problem is not
ignition related. A spark miss will be readily apparent. Now note RPM
of engine. Ground out one cylinder by contacting ignition tester and a
good ground on engine, Figure 1-11. Note RPM loss. Then ground out
the other spark plug and note the RPM loss. If the difference between
the two cylinders does not exceed 75 RPM, the amount of work the
two cylinders are doing should be considered equal.
If the RPM loss is greater than 75 RPM this indicates that the grounded
cylinder with the least RPM loss is the weakest of the two cylinders.
Look to that cylinder for a problem.
Example:
Engine RPM - Both Cylinders = 3400 RPM
Engine RPM - #1 Cylinder Grounded = 3300 RPM
Engine RPM - #2 Cylinder Grounded = 3100 RPM
Conclusion: #1 cylinder is weakest of the two cylinders.
The cylinder balance test will also detect a cylinder that is not functioning. When grounding out one cylinder there will be no RPM loss. When
the other cylinder is grounded out the engine will stop.
Model Normal Compression
GTH/GTV-760 130-160 psi
GTH/GTV-990/1000 160-190 psi
CYLINDER LEAKDOWN TEST
A cylinder leak down test will indicate the condition of the cylinder. It
will assist in troubleshooting the engine’s condition such as leaking
valves or rings.
On some testers there will be two gauges, one will be the incoming
air pressure and the other will measure the percent of cylinder leakage
(see Figure 1-12).
CYLINDER LEAK DOWN TEST PROCEDURE:
1. Piston must be at TDC of the compression stroke.
2. Install the tester into the spark plug hole.
3. The crankshaft/flywheel must be safely locked down to prevent
turning.
4. Pressurize the cylinder to 90 psi.
5. Observe the leakage of the cylinder and where the air is coming
from.
NOTE: If leaking into intake or exhaust port, check lash, valve face,
and seat condition.
1-5
SECTION 1: GENERAL INFORMATION
INLET GUAGE
COMPRESSED
AIR IN
AIR PRESSURE
REGULATOR
RED RANGE INDICATES
UNACCEPTABLE LEAKAGE
OUTLET
GUAGE
PRESSURE SET
POINT
0
0
OUTLET GUAGE
PRESSURE
0
REGULATOR
ADJUSTMENT
KNOB
NEEDLE INDICATES
MINIMAL AIR LEAKAGE
GREEN RANGE INDICATES
ACCEPTABLE LEAKAGE
NOTE: A twin cylinder engine will run well on one cylinder as long
as the power required for the application does not exceed the power
produced by the one cylinder.
EQUIPMENT AFFECTING ENGINE OPERATION
Frequently, what appears to be a problem with engine operation, such
as hard starting, vibration, etc., may be the fault of the equipment
rather than the engine itself. Listed are the most common effects of
equipment problems, and what to look for as the most common cause.
HARD STARTING OR WILL NOT START:
1. Loose belt - a loose belt like a loose blade can cause a backlash
effect, which will counteract engine cranking effort.
2. Starting under load - see if the unit is disengaged when engine is
started; or if engaged, should not have a heavy starting load.
Figure 1-12. Cylinder Leakdown Tester
RESULTS:
1. 0-10% Cylinder is good
2. 10-30% there may be a problem
3. 30-100% Cylinder requires repair
THINGS WHICH AFFECT BOTH CYLINDERS:
1. Carburetion
2. Crankcase vacuum
3. Ignition timing
a. A partially sheared flywheel key will effect ignition timing and
engine performance.
THINGS WHICH AFFECT ONE CYLINDER:
1. Spark plug
a. A fouled spark plug may indicate the carburetor is out of
adjustment.
2. Leak in spark plug wire
3. Head gasket
4. Intake manifold
a. A leak at either end of the intake manifold will only affect one
cylinder, not both.
5. Valves
3. Check remote control assembly for proper adjustment.
4. Check interlock system for shorted wires, loose or corroded
connections, or defective modules or switches.
ENGINE WON'T STOP:
1. Check equipment ignition stop switch.
2. Check for loose or disconnected equipment stop switch wire.
3. Check ground wire harness on engine.
a. See Section 2 for test procedure.
VIBRATION:
1. Unit load out of balance (pulley, clutch or blades) - remove and
replace.
2. Mounting bolts loose - tighten.
POWER LOSS:
1. Bind or drag in unit- if possible, disengage engine and operate
unit manually to feel for any binding action.
2. Unit load has excess drag.
NOISE:
1. Engine coupling or pulley - an oversize or worn coupling can result
in knocking, usually under acceleration. Check for fit or tightness.
2. Equipment needs lubrication.
6. Rings
7. Piston
8. Cylinder
1-6
SECTION 2: IGNITION
A
B
C
ENGINE
GROUND
HARNESS
POSITIVE METER
TEST LEAD
CYL #2
IGNITION
GROUND
WIRE STUD
CYL #1
NEGATIVE METER
TEST LEAD
GENERAL INFORMATION
Generac GTH/GTV-760/990 OHVI V-Twin engines use a magneto
ignition: an ignition coil with a self-contained transistor module (no
moving parts). Two magneto ignition coils are used, with a flywheel
containing a permanent magnet.
NOTE: The magneto ignition system requires a minimum of 300
RPM to produce a consistent spark.
ENGINE WIRING HARNESS
The engine wiring harness consists of a ground wire with a diode for
each ignition coil and a separate wire for the carburetor solenoid. The
engine ground wires are connected to the wiring harness provided by
the equipment manufacturer.
NOTE: Models built after 2007 will have the diodes built into
the ignition coils or spark plug leads. Check the wire harness.
If there are no diodes in the harness, perform test on the coil
ground terminal.
See Figure 2-4.
TESTING GROUND WIRES:
Use a Digital Multimeter (Figure 2-1) to test the ground wires.
The following test will be made with the meter in the Diode Test position.
attached for remainder of test.
5. Touch BLACK test lead probe to terminal "B."
a. If meter "Beeps" once, diode is OK.
b. If meter makes a continuous tone, diode is defective (shorted).
Replace ground harness.
c. If meter displays "OL," diode is defective (open). Replace ground
harness.
6. Now repeat test for terminal "C." Results must be the same.
7. Replace wiring if defective.
8. If wiring tests good, proceed to IGNITION COILS section to replace
defective coil.
Note: See “Diode Failure Diagnosis”, Figure 2-3.
2
In the Diode Test position, the meter will display the forward voltage
drop across the diode(s). If the voltage drop is less than 0.7 volts,
the meter will "Beep" once as well as display the voltage drop. A
continuous tone indicates continuity (shorted diode) An incomplete
circuit (open diode) will be displayed as "OL."
Figure 2-1. Digital Multimeter
1. Insert RED test lead into
2. Inser t BLACK test lead into the “COM” receptacle in meter.
receptacle in meter.
Figure 2-2. Testing Ground Wire
SWITCH ON TURNED OFF CAUSE
Engine Runs
Shuts Off OK 1 Closed Diode
On 1 Cylinder
Engine Runs
(Both Cylinders)
Won't Run
Only One
Cylinder
1 Open Diode
2 Closed Diodes
(No Spark)
Engine Runs
(Both Cylinders)
Engine Won't Shut
Off
2 Open Diodes
Figure 2-3. Diode Failure Diagnosis
WIRE HARNESS CHECK
3. Rotate selector to (Diode Test) position.
4. Insert RED test lead clip into connector "A" (Figure 2-2). Leave
IGNITION COIL TESTING:
If ignition does not have spark, disconnect ground wire from ignition
2-1
SECTION 2: IGNITION
DIODE (BUILT INTO COIL)
SPARK PLUG
GROUND
WIRE
HARNESS
DIODE (BUILT INTO COIL)
SPARK PLUG
Figure 2-4. Engine Wiring Harness
ground stud on engine and re-check. If ignition now has spark, check
wire harness for pinched wires, broken insulation or bad diode (if
equipped). If there is no spark, proceed to Removing Ignition Coil
section.
REMOVING AND INSTALLING WIRE HARNESS:
1. Remove spark plug leads.
IGNITION GROUND WIRE
DIODE BUILT IN HARNESS
ON OLDER MODELS
Note: The flywheel does not need to be removed to service ignition
except to check the flywheel key.
2. Remove intake manifold and cover intake ports with a shop
towel.
3. Remove rotating screen and blower housing.
4. Disconnect stop switch wire(s) at ignition coil(s).
5. Reverse order of above to install new wire harness.
REMOVING IGNITION COILS:
The condition of the ignition coils can be accurately diagnosed
using a spark tester (Generac P/N 0C5969) as described in
"TROUBLESHOOTING" Section 1.
1. Remove spark plug leads.
2. Remove intake manifold and cover intake ports with a shop
towel.
3. Remove rotating screen and blower housing.
4. Disconnect ground wire(s) at ignition coil(s).
5. Remove ignition coil screws and remove ignition coil(s). See
Figure 2-5.
Figure 2-5. Removing Ignition coil
INSTALL IGNITION COILS:
1. Turn flywheel so magnet is away from ignition coil.
2. Install ground wire onto tab terminal on ignition coil.
Note: Make sure wires are routed over ignition coil mounting posts
and away from flywheel.
3. Assemble ignition coil to engine, Figure 2-6.
a. Mounting holes in ignition coil are slotted. Push ignition coil
away from flywheel as far as possible and tighten screws.
4. Repeat for second ignition coil.
5. See Adjust Ignition Coil Air Gap.
2-2
SECTION 2: IGNITION
FLYWHEEL
REMOVE FLYWHEEL:
1. Remove two screws that attach fan and fan retainer to
flywheel.
2. Remove fan retainer and fan.
GROUND WIRE ROUTING
Figure 2-6. Installing Ignition coil
ADJUST IGNITION COIL AIR GAP:
1. Rotate flywheel until magnet is aligned with ignition coil
laminations.
2. Place 0.20-.30 mm (.008"-.012") thickness, non-magnetic gauge
between magnet and ignition coil laminations, Figure 2-7.
3. Loosen mounting screws so magnet will pull ignition coil against
thickness gauge.
a. Torque screws to 4.75 Nm (40 in. lbs.).
0.20-0.30mm SHIM
SOCKET
WRENCH
3. Loosen flywheel nut until it is flush with end of crankshaft threads
(Figure 2-8.)
4. Install flywheel puller.
5. Tighten puller screws equally until flywheel loosens, Figure 2-9.
6. Remove puller, nut, washer and flywheel.
Figure 2-8. Removing Flywheel Nut
2
GROUND WIRE TERMINAL
Figure 2-7. Adjusting Air Gap
4. Rotate flywheel to remove thickness gauge.
5. Repeat for second ignition coil.
Note: Route ignition coil ground wire under breather tube and away
from the flywheel (see Figure 2-9).
Caution: Flywheel puller bolts may damage lighting coil if turned
*
in too far.
Caution: DO NOT strike flywheel with a hard object or a metal
*
tool as this may cause flywheel to shatter in operation. Always
use approved flywheel removal tools.
INSPECT FLYWHEEL KEY, KEYWAYS, FLYWHEEL AND
CRANKSHAFT:
Check flywheel key for damage. Check flywheel for cracks or keyway
damage. Also check crankshaft keyways and taper for damage, Figure
2-10. Replace crankshaft, if damaged.
2-3
SECTION 2: IGNITION
COIL WIRE ROUTED
UNDER BREATHER
FLYWHEEL
NUT
Figure 2-9. Removing Flywheel
INSPECT HERE
Figure 2-10. Check Flywheel And Crankshaft
INSTALL FLYWHEEL:
Note: CLEAN flywheel and crankshaft taper removing all oil, dirt
or grease.
1. Insert flywheel key into crankshaft.
Figure 2-11. Torquing Flywheel Nut
Figure 2-12. Installing Flywheel Fan
3. Install washer and flywheel nut.
a. Torque flywheel nut to 204.0 Nm (150 ft. lbs.), Figure 2-11.
4. Assemble fan and retainer to flywheel, Figure 2-12.
a. Torque screws to 21.7 Nm (182 in. lbs.).
2. Align keyways and assemble flywheel to crankshaft.
2-4
SECTION 3: CARBURETION AND FUEL SYSTEM
CARBURETOR TYPES
All Generac gasoline powered OHVI V-Twin engines utilize a
two-barrel type carburetor. Some LP engines use a single barrel
carburetor.
CARBURETOR REMOVAL - VERTICAL SHAFT
1. Unclip choke link from bellcrank and remove link from
carburetor.
2. Disconnect fuel-shutoff solenoid by unplugging the power wire.
3. Disconnect breather tube and EVAP hose if equipped.
4. Separate throttle link balljoint from carburetor by rotating the ball
socket.
5. Disconnect the fuel line clamp and the fuel line.
SPEED
CONTROL
LEVER
SLOW
BREATHER
HIGH
CHOKE
LINK
6. Remove the four nuts holding the carburetor and plenum to the
intake manifold (see Figure 3-6).
7. Remove the plenum, carburetor and gaskets from the manifold
and discard the gaskets.
CARBURETOR REMOVAL – HORIZONTAL SHAFT
1. Remove air cleaner cover and air cleaner.
2. Unthread yellow plastic knob from Summer/Winter intake control
(if equipped)
3. Remove dipstick tube hold down bolt and remove tube assembly
(see Figure 3-3).
4. Remove the four nuts and one bolt that retains the air cleaner base,
breather tube and EVAP hose if equipped; remove base (see Figure
3-3).
5. Remove fuel line clamp and fuel line from top of carburetor.
4 NUTS
BOLT
3
BELL CRANK
Figure 3-1. Vertical Shaft Carburetor
CLIP
DIPSTICK TUBE &
HOLD DOWN
Figure 3-3. Horizontal Shaft Carburetor
THROTTLE
LINK
Figure 3-2. Vertical Shaft Carburetor
Figure 3-4. Horizontal Shaft Carburetor
3-1
SECTION 3: CARBURETION AND FUEL SYSTEM
CHOKE
LINK
Figure 3-5.
6. Remove choke link (Figure 3-5), throttle link (Figure 3-4) and fuel
shut-off solenoid wire from carburetor.
7. Slide carburetor off mounting studs.
CARBURETOR CLEANING
For cleaning purposes, the carburetor's float bowl may be removed.
It is recommended that all jetting be left in place while cleaning the
carburetor. Be sure to use a cleaner that won't damage rubber, neoprene, or plastic parts.
Note: The left and right main jets are different sizes.
If the fuel-shutoff solenoid is suspected of being faulty, it is replaceable
by simply unthreading it from the float bowl, and installing a new one
in its place. It can be checked by applying 12 volts to it. If you hear it
click, it is most likely working properly. If there is anything else wrong
with the carburetor, it is recommended that the entire carburetor be
replaced with a new one.
MANIFOLD
PLENUM
PLENUM
GASKET
CARBURETOR
GASKET
Figure 3-6.
8. Reinstall choke link on carburetor and clip the link into the
bellcrank.
9. Perform a static governor adjustment. (See “Static Governor
Adjustment”, page 4-2)
10. Start engine and allow to warm up for 5 minutes.
11. Move speed control lever to slow speed position and hold throttle
lever against idle stop screw.
12. Adjust the idle top screw to maintain ~1800 RPM idle.
13. Slowly move speed control lever to high speed position.
Note: Be careful not to lose the spring that is located inside
the fuel shutoff solenoid when removing the plunger.
CARBURETOR INSTALLATION - VERTICAL SHAFT
1. Slide new carburetor gasket and carburetor onto the studs.
2. Slide new plenum gasket and plenum onto the studs.
3. Install the four nuts and torque to 5.4 Nm (48 in. lbs.).
4. Connect the fuel line and clamp.
5. Reassemble the throttle link to the balljoint on the carburetor.
6. Connect the breather tube and EVAP hose if equipped.
7. Connect the fuel-shutoff solenoid.
Figure 3-7.
Note: The high speed screw may need adjusting to reach the speed
control stop without exceeding 3800 RPM.
14. With the speed control in the high speed position, adjust the high
speed screw to obtain the desired engine speed. Do not exceed
3800 RPM.
3-2
CLINCHING
SCREW
SECTION 3: CARBURETION AND FUEL SYSTEM
10. Move speed control lever to slow speed position and hold throttle
lever against idle stop screw.
11. Adjust the idle stop screw to maintain ~ 1800 RPM idle.
12. Slowly move speed control lever to high-speed position.
IDLE
13. With the speed control in the high speed position, adjust the high
speed screw to obtain the desired engine speed. Do not exceed
3800 RPM.
FUEL PUMP
The fuel pump supplied with the engine is a pulse type pump. It uses
crankcase vacuum pulses drawn from the valve cover to pump the
fuel. It is capable of priming at 12" (30.5 cm) maximum lift, and has
a maximum outlet pressure of 1.5 psi. If the fuel pump is not working
properly, check the vent hole on the top of the pump for obstructions.
3
Figure 3.8.
CARBURETOR INSTALLATION – HORIZONTAL SHAFT
1. Install a new carburetor gasket and carburetor onto the studs.
2. Install air cleaner base, breather tube and EVAP hose (if
equipped), bolt and nuts and torque to 5.4 Nm (48 in. lbs.).
3. Re-attach choke and throttle links and solenoid wire to
carburetor.
4. Install fuel line and fuel line clamp.
5. Install oil fill tube and hold down bolt and torque to 4.7 Nm (40
in. lbs.).
6. Install air cleaner and air cleaner cover.
7. Install yellow knob for Summer/Winter control.
8. Perform a static governor adjustment. (See “Static Governor
Adjustment”, page 4-2)
9. Start engine and allow to warm up for 5 minutes.
If a fuel pump other than the factory recommended pump is used, the
fuel line pressure at the carburetor inlet must not exceed 3 psi. Pressures in excess of 3 psi may cause an over rich carburetor mixture
that would lead to engine damage.
TO
CARBURETOR
INLET
VENT HOLE
FUEL FROM
TANK
PULSE LINE
Figure 3-9. Fuel Pump
3-3
SECTION 3: CARBURETION AND FUEL SYSTEM
SPRING
RETURN
1 2 3 4 5 6
LOWER
DIAPHRAGM
UPPER
DIAPHRAGM
VENT: UPPER
VENT ASSEMBLY
FUEL
CHECK-
VALVE 1
FUEL
CHECK-
VALVE 2
HARDWARE
Figure 3-10. Fuel Pump Assembly
Fuel Pump Breakdown (see Figure 3-10):
1. Lower Spring Assembly
2. Lower Diaphragm
3. Check Valve Assembly
4. Upper Diagram
5. Upper Vent Assembly
6. Mounting Hardware x 2
As crankcase vacuum is built up the Lower Diaphragm pulls down
against the Spring Return and allows fuel to flow through Check-Valve
2. As pressure builds up in the crankcase, the Spring Return pushes
up against the Lower diaphragm, allowing fuel will flow through CheckValve 1 and out the fuel port.
LP (LIQUID) - FUEL SYSTEM
Proper service and repair is important to the safe and reli-
*
able operation of all gaseous fueled engines. Any servicing
or testing of a gaseous fueled engine must only be performed
by qualified personnel. Always follow applicable installation
and service procedures. An example of these requirements
is found in NFPA-58 for liquid propane. These are US Federal
standards. Worldwide standards vary. Local, city, and state
requirements may also have certain requirements that must
be observed.
LP (Liquefied Petroleum Gas) is a gaseous fuel and when stored under
pressure, becomes a liquid. Although a vapor forms at the top of the
tank, this particular system uses a liquid withdrawal method, drawing
liquid from the bottom of the tank.
This is accomplished with a special valve that is installed on a normal
propane cylinder with a tube that is attached to the valve and extends
to the bottom of the storage tank. Pressure in the tank forces liquid
propane through the tube when the valve is opened.
The Generac LP system starts with a pressure relief valve to prevent
excessive pressure from building in the system during shutdown.
This is followed by a 12 volt (normally closed) electric solenoid,
which prevents the flow of fuel when the ignition key is off. When the
ignition key is turned on, the solenoid opens and allows liquid LP to
flow to the regulator.
The liquid fuel vaporizer/regulator converts liquid propane to vapor.
The vaporizer/regulator uses either spent engine cooling or engine oil to
provide heat to aid in the evaporation process. The vaporizer/regulator
controls the vapor supply to an amount required by the engine. The
engine’s intake vacuum draws LP into the fuel mixer on an on-demand
need. When the engine is off, LP no longer flows from the vaporizer/
regulator to the engine (see Figure 3-32).
TROUBLE SHOOTING
CAUTION! Gaseous fuels are highly explosive; do not use flame
*
or heat to test the fuel system for leaks. LP gas is heavier than
air and tends to settle in low areas; even the slightest spark
can ignite these gases and cause an explosion.
Note: Don’t assume that the fuel system is the problem. Verify that
the engine has spark and enough compression to start the engine
before proceeding with the following steps.
3-4
SECTION 3: CARBURETION AND FUEL SYSTEM
TESTING THE FUEL SHUT-OFF SOLENOID
1. Remove the spark plug wires from each spark plug to prevent
accidental starting of the engine.
2. Check for 12 volts DC at the solenoid terminal.
See Figure 3-11.
a. Place one hand on the fuel solenoid and turn the ignition switch to
the run position. You should be able to feel the solenoid actuate
as well as hear an audible click. Replace the solenoid if it does
not actuate. Some systems will delay power to the solenoid until
full oil pressure is reached during cranking.
3. If the solenoid is opening properly, proceed
to “TESTING AND REPAIRING THE LPG
VAPORIZER/REGULATOR.”
4. Reconnect the spark plug leads when finished
COIL BOLT
COIL SPOOL
RESEVOIR BOLT
Figure 3-12. LPG Solenoid Valve Torque and
Lubrication Points
SEALING GASKET
SEALING GASKET
SEALING GASKET
SEALING GASKET
3
12 VOLT WIRE
Figure 3-11. LPG Solenoid Valve
DISASSEMBLY AND ASSEMBLY OF
LPG SOLENOID VALVE
If the solenoid valve is removed for cleaning or replacing the filter, it is
recommended that the special synthetic sealing gaskets be replaced.
When installing new sealing gaskets, they should be lubricated using
an O-ring lubricant. DO NOT RE-USE O-RINGS!
For improving the functional features and lifetime of the solenoid, it
is recommend that the gaskets and filter be replaced after 500 hours
of operation.
NOTE: For correct solenoid valve fitting, it is essential that the
following torque values be observed:
1 Coil Bolt 7.85 Nm (70 in. lbs.)
2 Reservoir Bolt 11.8 Nm (104 in. lbs.)
3 Coil Spool: 16.6 Nm (147 in. lbs.)
TESTING AND REPAIRING LPG
VAPORIZER/REGULATOR
SPECIAL EQUIPMENT REQUIRED:
1. Air pressure at 100 psi, and air pressure gauge 0-15 psi, with
connecting hose and fittings to attach to the 1/8” NPT female pipe
connection.
2. Liquid leak detector to check for leaks (recommended).
REPAIR KIT CONTENTS:
(Refer to Parts Manual for specific part numbers.)
Pin, Pivot, Secondary Reg Lever
Lever, Assembly Reg Secondary
Diaphragm, secondary
Assembly. Diaphragm, primary
Assembly, Lever, Primary
Pin, Pivot, Primary
3-5
SECTION 3: CARBURETION AND FUEL SYSTEM
NOTE: test regulator on engine first or, for scheduled maintenance,
proceed to "remove regulator and dismantle as follows".
1. Make sure the fuel tank(s) have an adequate supply of fuel.
2. Make sure the valve on the tank is fully open (turned counterclockwise).
Note: This fuel system is under high pressure.
3. While the fuel is off, install the primary pressure test gauge at the
1/8” primary test port opening at the side of the regulator, marked
“PRI”. See Figure 3-14.
4. Disconnect the vapor hose at the Carburetor or Carburetor
Adapter.
5. Turn on the ignition to open the fuel solenoid valve.
6. If the engine is equipped with an engine controlled safety switch,
bump the starter to make contact and open the fuel solenoid valve.
7. Primary pressure should be 0.5 to 4.5 psi and hold
pressure.
8. If primary pressure is too high or too low and leakage is observed
at the vapor hose, the regulator must be re-moved, disassembled,
cleaned and new parts installed.
REMOVE REGULATOR AND DISASSEMBLE AS FOLLOWS:
Caution! Prior to the removal of any LP system components,
*
disconnect the battery and turn off the fuel supply at the tank(s).
1. Remove the five secondary cover screws, 10-32 x 0.630”, and lift
the cover off the regulator body and secondary diaphragm (see
Figure 3-13). The cover has a tendency to stick to the diaphragm
and gasket. A slight tap on the edge of the cover with a screwdriver
handle or a soft face hammer will loosen the cover.
Note: Do not pry in between the cover and the body. Damage to the
sealing surface may result.
2. After the cover has been removed, lift up an edge of the diaphragm.
Observe how it is attached to the secondary lever. See Figure 3-14.
Figure 3-13. Remove Five Secondary Cover Screws
4. Remove the four screws, 10-32 x 0.630”, holding the primary
diaphragm cover in place. If the cover sticks, use a screwdriver
handle or soft-faced hammer to dislodge it. Observe that the
longer (2),10-32 x 1.0”, of the six screws are at the top of the
cover. Remove primary spring. See Figure 3-16.
3. Remove the two screws, 10-32 x 0.310”, holding the secondary lever pivot pin and remove the secondary lever and spring.
The secondary pivot pin is 1.20” long. See Figure 3-15.
PRESSURE TEST POINT
Figure 3-14. Lift Edge of Diaphragm
5. Remove the primary diaphragm. See Figure 3-17.
6. Remove the two screws, 8-32 x 0.375” long. See Figure
3-18.
Note: Remove oil and foreign deposits from all chambers and
parts. DO NOT APPLY LIQUID CLEANERS TO THE DIAPHRAGMS
AND NEOPRENE FACED VALVES.
3-6
Figure 3-15. Remove Secondary Lever and Spring
SECTION 3: CARBURETION AND FUEL SYSTEM
3
Figure 3-18. Remove/Replace Two Screws 8-32 x 0.375” long
REASSEMBLY OF REGULATOR:
Figure 3-16. Remove Primary Diaphragm Cover
and Primary Spring
1. Carefully clean and inspect all metal parts-springs, levers, pivot
pins and screws. Replace all parts that are included in the repair
and rebuilding kits.
2. Carefully clean the body casting and inspect all sealing surfaces.
Wipe with a clean rag. Inspect the primary section for foreign
materials that might loosen and damage the soft face valves.
3. Blow out the fuel inlet passage and outlet passages. Be sure no
foreign material remains in these passages.
4. Inspect the primary orifice and the secondary orifice for nicks
scratches or uneven wear.
IMPORTANT! If the primary or secondary seats show any of the
above mentioned conditions, the regulator is not rebuildable and
must be replaced.
5. Lay the regulator flat on a clean working surface with the primary
section up.
6. Replace the primary pivot pin, 0.890”, bridge and two screws,
8-32 x 0.375”. Tighten screws evenly to 30 in. lbs. ±3 in. lbs.
(3.39 Nm ± 0.339 Nm). Rock the primary lever assembly to
ensure that it pivots freely. See Figure 3-18.
7. Engage the primary diaphragm pin with the slot in the primary
lever. Rotate the diaphragm to align the cover screw holes as
shown in Figure 3-19.
Figure 3-17. Remove Primary Diaphragm
8. Place primary spring, small side up, on top of diaphragm. Install
primary cover and screws. Remember, the 2 longer, 10-32 x 1.0”,
screws go to the top of the primary cover. Tighten evenly, in a
criss-cross pattern, to 30 in. lbs. ±3 in. lbs. (3.39 Nm ±0.339
Nm). See Figure 3-20.
3-7
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