Yamaha Motor 20C Manuel D'entretien page 258

TRBL
SHTG
Is the compression of crankcase normally?
Check the leakage of compression from the
crankcase.
Is there any damage on the cylinder?
IF THE TROUBLE HAS NOT BEEN FOUND,
START THE ABOVE CHECKS ALL OVER AGAIN.
1
Is the starter mounting position correct?
Can the flywheel be turned by hand?
Remove the lower unit and can the flywheel be
turned by hand?
Disassemble the power head and check.
2
Is the spark-plug installed correctly?
Remove the cylinder-head and check, is the pis-
ton holed?
Is the head gasket in good condition?
ENGINE IS HARD TO START OR WILL NOT START
YES
NO
YES
YES
YES
YES
NO
YES
NO
Check the following parts and replace as
necessary:
1) Oil seal
2) Crank case -
scratches on mating surfaces.
YES
Replace the crank cylinder assembly.
NO
Correct it.
NO
Disassemble the recoil starter and
check it. (P.5-27)
NO
Check the lower unit; (P.6-1)
1) Impeller blades are caught;
2) Gear/bearing damaged;
3) Shim adjustment wrong
NO
Install it correctly.
YES
Replace.
NO
Replace.
9-3
E
cracked, distortion,