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pressure. If positive pressures build up within the crankcase from a clogged breather or from piston blow-
by, oil will be forced out of an engine at oil seals, gaskets or any other available spot.
These are just a few of the more common indicators. Numerous others exist and are obvious to the
experienced mechanic. Often the cause will become apparent in view of the particular condition of the
part. Always look for these signs when disassembling an engine prior to reconditioning.
DISASSEMBLY PROCEDURE
The following is intended as a guide to disassembly of the standard engine models - the sequence
may have -to be varied slightly to facilitate removal of special equipment or accessory items such as motor
- generators, starters, instrument panels, etc.
1.
Disconnect lead and remove spark plug.
2.
Close valve, remove fuel line at carburetor.
3.
Remove air cleaner from carburetor intake.
4.
Remove carburetor.
5.
Remove motor generator if so equipped.
6.
Remove blower housing, cylinder baffle and head baffle.
7.
Remove rotating screen and starter pulley.
8.
Flywheel is mounted on tapered portion of the crankshaft. Use of a puller is recommended for
9.
removing flywheel.
10.
Remove breaker point cover, breaker point lead, breaker assembly and push rod if so equipped.
11.
Remove magneto assembly.
12.
Remove valve cover and breather assembly. 12. Remove cylinder head.
13.
Raise valve springs with a spring compressor and push valve keepers off valve stems. Remove
valve spring retainers, springs and valves.
14.
Remove oil base and unscrew connecting rod cap. Remove piston assembly from cylinder block.
15.
Remove crankshaft, oil seals and, if necessary anti-friction bearings. It may be necessary to press
crankshaft out of cylinder block. Bearing plate should be removed first if this is done.
16.
Turn cylinder block upside down and, using a small punch, drive camshaft pin out from power-
take-off side of engine. Pin will slide out easily after it is driven free of block.
17.
Remove camshaft and valve tappets.
18.
Loosen and remove governor arm from governor shaft.
19.
Unscrew governor bushing nut and remove governor shaft from inside of cylinder block.
20.
Loosen (do not remove) screw located to lower right of governor bushing nut until governor gear
is free to slide off stub shaft.
ENGINE RECONDITIONING
All parts should be thoroughly cleaned - dirty parts cannot be accurately gauged or inspected
properly for wear or damage. There are many commercially available cleaners that quickly remove grease,
oil and grime accumulation from engine parts. If such a cleaner is used, make sure that all trace of the
cleaner is removed before the engine is reassembled and placed in operation. Even small amounts of these
cleaners quickly break down the lubricating properties of engine oils.
1.
INSPECTION
A.
Gasket surfaces - Check all surfaces to make sure that they are free of gasket fragments and sealer
materials. Surfaces must also be free of deep scratches or nicks.
B.
Bearings - (Crankshaft) - One bearing is pressed into the cylinder block - the other is located in the
bearing plate. Do not remove bearings unless they show signs of damage and are to be replaced.
(See Reconditioning - Cylinder Block.) If the bearings turn easily and noiselessly and there is no
evidence of scoring or grooving on the races, the bearings can be reused.
