Service Manual

Section 11. Engine B
INTRODUCTiON
This section covers service procedures for the en-
gine block assembly.
A compression test can be
performed to determine the condition of the engine.
WARNING Accidental starting of the engine
can result in severe personal injury or death.
Disconnect the negatlve
(-) battery cable and
spark plug wire before servicing the engine,
controls,
or associated equipment.
ENGINE DlSASSEMBLY/ASSEMBLY
When complete engine disassembly is necessary,
first remove all complete assemblies. Individual
assemblies such as the carburetor can be disas-
sembled and repaired at another time.
Suggested Disassembly Order
1. Drain crankcase oil.
2. Disconnect all fuel, exhaust and electric lines.
3. Remove the engine from its mountings and
place it on a suitable bench or work stand.
4. Remove the muffler, chaff screen, blower
housing, cylinder air housing, etc.
5. Remove the air cleaner assembly, carburetor,
and air deflector.
6. Remove the ignition module.
7. Remove the flywheel using a puller.
8. Remove all accessories such as oil filter,
starter, intake manifold, exhaust manifold,
spark plug, etc.
9. Remove the valve cover and cylinder head
assembly.
IO. Remove the oil base carefully, keeping all end
play shims on their respective shafts.
1.1. Remove the balance shaft assemblies.
1 2. Remove the connecting rod and piston.
13. Remove crankshaft and camshaft assemblies.
Keep all parts in their respective orders. Keep valve
assemblies together. Analyze the reasons for parts
failure.
lock Assembly
Suggested Assembly Procedure
Engine assembly is normally the reverse of the dis-
assembly procedure, observing proper clearances
and torques. Use a torque wrench to assure proper
tightness. Coat the internal engine parts with oil as
they are assembled. After the internal engine parts
are assembled, the engine should turn over by hand
freely.
Use only genuine Onan parts and special
tools when reassembling your engine.
1. Install tappets, crankshaft and camshaft as-
2. Install the connecting rod and piston.
3. Install the balance shaft assemblies.
4. Install the oil base, reuse the original end play
5. Install the cylinder head assembly and lash
6. Install the accessories such as valve cover, oil
filter, starter, intake manifold, exhaust mani-
fold, spark plug, etc.
semblies.
shims on their respective shafts.
valves.
7. Install the flywheel and ignition module.
8. Install the air deflector, carburetor, and cleaner
9. Install the cylinder air housing, muffler, blower
assembly.
housing, chaff screen, etc.
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10. Install the engine on its mounting.
11. Connect all fuel, exhaust and electric lines.
12. Fill crankcase with oil.
Operation
Start the engine and check oil pressure. Run for ap-
proximately
15 minutes to bring engine to operating
temperatures. Check for oil leaks, fuel leaks, and
exhaust leaks. Adjust carburetor and governor for
speed, and sensitivity.
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