Compression Testing
Start and run outboard until it achieves operating temperature, then shut OFF.
Disconnect crankshaft position sensor (CPS) connector. Remove all spark plugs.
Install compression tester’s hose attachment into spark plug hole (14 mm threads).
Turn the key switch to the ON position.
While cranking outboard with starter, note maxi mum 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.
Powerhead Removal
Protect against hazardous fuel spray. Before starting any fuel system service, carefully relieve fuel system pressure. Refer to Relieving Fuel System Pressure on p. 168.
To prevent accidental starting while servicing, twist and remove spark plug leads.
Procedure
IMPORTANT: Before removing the powerhead
Engine in Vertical Position
Remove the top engine cover. Then remove the 4 inch plug from the center frame. Next remove the 3.5 inch plug from the air duct and the thread protector from the flywheel threads.
- 4 inch plug
- 3.5 inch plug
- Thread protector
Remove the front cover. Then disconnect all cables, buss cables and hoses from the engine.
Remove the rear cover, starboard and port frames and front frame. Refer to Engine Cover and Frame Service on p. 55.
Remove the rigging grommets from the power head.
