Checking, Disassembling And Servicing; Checking And Adjusting; Engine Body - wsm STW37 Workshop Manual

STW34, STW37, STW40, WSM

4. CHECKING, DISASSEMBLING AND SERVICING

[1] CHECKING AND ADJUSTING

(1) Engine Body

Compression Pressure
1. Operate the engine until it is warmed up.
2. Stop the engine and disconnect the 2P connector from the stop
solenoid in order to inject fuel.
3. Remove the air cleaner, the muffler and all injection nozzles.
4. Set a compression tester (Code No. 07909-30208) with the
adaptor to the nozzle hole.
5. Keep the engine stop lever at "Stop Position".
6. While cranking the engine with the starter, measure the
compression pressure.
7. Repeat steps 4 through 6 for each cylinder.
8. If the measurement is below the allowable limit, apply a small
amount of oil to the cylinder wall through the nozzle hole and
measure the compression pressure again.
9. If the compression pressure is still less than the allowable limit,
check the top clearance, valve and cylinder head.
10. If the compression pressure increases after applying oil, check
the cylinder wall and piston rings.
NOTE
• Check the compression pressure with the specified valve
clearance.
• Always use a fully charged battery for performing this test.
• Variances in cylinder compression values should be under
10 %.
Factory specification
Compression pressure
Allowable limit
1-S12
ENGINE
3.6 to 4.0 MPa
2
36 to 41 kgf/cm
520 to 580 psi
2.5 MPa
2
26 kgf/cm
370 psi
9Y1211109ENS0004US0
KiSC issued 11, 2014 A