Taper Pin Tool
Compression Testing
Start and run outboard until it achieves operating temperature, then shut OFF.
Disconnect crankshaft position sensor (CPS) connector. Remove all spark plugs.
Advance throttle linkage to WOT.
Install compression tester’s hose attachment into spark plug hole (14 mm threads).
While cranking outboard with starter, note maximum pressure reading on gauge. Repeat procedure for each cylinder.
If engine shows a variation greater than 15 psi
(100 kPa) between cylinders, check for:
- damaged cylinder head
- damaged pistons
- broken or stuck piston rings
- scored cylinder walls
Return throttle to idle position and reconnect CPS connector. Replace spark plugs. Refer to Spark Plug Indexing on p. 84.
