Generac Power Systems OHVI GSH 220 Service Manual page 9

crankcase and contaminate the oil, forming an abrasive mixture
which will cause wear on all of the internal moving parts.
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 clean-
ing. Instruct the customer on proper care, to assure long
engine life.
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 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.
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 clas-
sified as one or a combination of the following:
. Will not start
2. Hard starting
. Lack of power
. 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 fol-
lowing order:
. Fuel
2. Ignition
. 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 check-up
SeCTIoN 1: GeNerAl INForMATIoN
procedure is the same for all engine models, while any varia-
tion, by model, will be shown under the subject heading.
CHECK FUEL:
• Are the tanks full?
• Is the fuel stale?
• Is the tank vent open?
• Is the fuel shutoff valve open?
CHECK IGNITION:
See Section 2 "IGNITION".
CHECK COMPRESSION:
To check engine compression, remove the spark plug. Insert
an automotive type compression gauge into the spark plug
hole. Crank the engine until there is no further increase in
pressure. The highest reading obtained is the engine compres-
sion pressure.
190-220cc Engines: Minimum 60psi
320-410cc Engines: Minimum 55psi
These minimum readings may appear low. This is due to the
engine being equipped with a compression release mechanism
to minimize starting effort. Actual running compression will
be much higher (see Page -).
If compression is poor, look for one or more of the follow-
ing causes:
• Loose cylinder head bolts.
• Failed cylinder head gasket.
• Burned / worn valves or valve seats.
• Insufficient valve clearance.
• Warped cylinder head.
• Warped valve stem or worn valve guides.
• Worn or broken piston ring(s).
• Worn or damaged cylinder bore.
• Broken connecting rod.
CYlINder leAkdowN TeST
A cylinder leakdown tester may be used to test the sealing
capability of the compression components of each cylinder
and quickly identify the problem component.
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 the tester there will be two gauges, one will be the
incoming air pressure and the other will measure the percent
of cylinder leakage.
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