Looking for some insight on a 1994 Johnson 60hp triple (J60TTLERS) that has a rough idle but runs great everywhere else.
Compression: ~125 PSI even across all 3 cylinders.
Spark: Strong. Snaps a 7/16" jump from all three coils.
Fuel: Not running lean as far as I can tell. Holding the primer solenoid just bogs the engine down (doesn't smooth out the idle), and squeezing the primer bulb has no effect.
Performance: WOT is beautiful. Smooth RPMs above 1200 RPM as far as I can feel and hear.
I am getting a milky residue on all 3 plugs. If I don't clean them and fog the engine immediately after use, I get physical rust on the rag if I wipe the plugs down after a few days.
I’m suspecting a leak at the exhaust manifold gasket is letting just enough water in the cylinders to cause the engine to stumble at idle.
Has anyone had this experience? Appreciate any insights before I tear into it.
Edit to add; Link and sync performed as per the manual. Timing does seem too far retarded at idle (4°±1 BTDC to the manuals 2°±1 BTDC) adjusting with the idle stop screw brings the timing in line, but lifts the idle rpm up above 1000. Engine wants to cut out or shake violently between 800-900rpm.
WOT timed via Reeves method at 17± -4°. Haven't had the nerve to check it at WOT on the water, but it sounds fine.
Compression: ~125 PSI even across all 3 cylinders.
Spark: Strong. Snaps a 7/16" jump from all three coils.
Fuel: Not running lean as far as I can tell. Holding the primer solenoid just bogs the engine down (doesn't smooth out the idle), and squeezing the primer bulb has no effect.
Performance: WOT is beautiful. Smooth RPMs above 1200 RPM as far as I can feel and hear.
I am getting a milky residue on all 3 plugs. If I don't clean them and fog the engine immediately after use, I get physical rust on the rag if I wipe the plugs down after a few days.
I’m suspecting a leak at the exhaust manifold gasket is letting just enough water in the cylinders to cause the engine to stumble at idle.
Has anyone had this experience? Appreciate any insights before I tear into it.
Edit to add; Link and sync performed as per the manual. Timing does seem too far retarded at idle (4°±1 BTDC to the manuals 2°±1 BTDC) adjusting with the idle stop screw brings the timing in line, but lifts the idle rpm up above 1000. Engine wants to cut out or shake violently between 800-900rpm.
WOT timed via Reeves method at 17± -4°. Haven't had the nerve to check it at WOT on the water, but it sounds fine.
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