Compression Check: Testing and Inspection

INSPECT COMPRESSION
a. Warm up and stop engine.
b. Remove ignition coil.
c. Remove spark plugs.
d. Inspect cylinder compression pressure.
SST 09992-00500
1 Insert a compression gauge into the spark plug hole.
2 Fully open the throttle.
3 While cranking the engine, measure the compression pressure.
Compression pressure: 1,300 kPa (13.3 kgf/cm2, 189 psi)
Minimum pressure: 1,000 kPa (10.2 kgf/cm2, 145 psi)
Difference between each cylinder: 100 kPa (1.0 kgf/cm2, 15 psi)

NOTICE:
- Always use a fully charged battery to obtain engine speed of 250 rpm or more.
- Check other cylinder's compression pressure in the same way.
- This measurement must be done in as short a time as possible.

4 If the cylinder compression in one more cylinders is low, pour a small amount of engine oil into the cylinder through the spark plug hole and repeat steps 1 through 3 for cylinders with low compression.

HINT:
- If adding oil helps the compression, it is likely that the piston rings and/or cylinder bore are worn or damaged.
- If pressure stays low, a valve may be sticking or seating is improper, or there may be leakage past the gasket.