Partially Scored Cylinder

[tljungman]

I have a 1997 115 hp (115ETLH). The compression was low on the right lower cylinder. When I pulled the head the cylinder was scored only on part of the circumference of the cylinder. Viewing from the top of the cylinder the scoring starts at about 7 o'clock, where the exhaust port starts, and the scoring continues around the cylinder clockwise, the full length of the exhaust port and beyond, and the scoring stops at about 11 o'clock. The rest of the cylinder feels fine by touch. I'm considering a rebuild, but I wonder what caused this. I have not removed the piston yet, which would give me more information. Could the problem be an oil injection problem with only a portion of one cylinder affected? When the engine was idling poorly, and before I checked the compression, I checked the oil pump and the linkage had the pump set above minimum at idle. I adjusted the oil pump to minimum at idle, following the instructions of my SELOC Repair Manual. I then ran the engine a few times, with perhaps some mild improvement at idle, but the last time I ran the engine on the water I had some harsh sounds at high speed with the engine stalling and had trouble restarting the engine. I have since started the engine with a flushing device, but it still stalls at idle which has been the problem.

[boats.net]

Probably a plugged carb(running too lean) or possible overheat.