I put in a Moyer exchange engine in my Apache 37 in 2007. After a while of diagnosing overheating issues, she ran great. All of 2008 she ran great. On start-up this season she ran really roughly before launch. #1  (new) plugs looked extremely fouled. Used MMO to free up what was thought to be stuck valves. Started running well. Launched boat. When I initially put her in gear I heard what I can only describe as a squeal. Kind of like a fan belt slip, but it wasn't that. Motored over to local harbor (not mine) with intermittent noise and left boat with local "boat genius" for a week. His diagnosis - transmission.
Here's the issue. It only makes this noise, which now sounds more like a "thump", when in gear and it's intermittent. I can rev the engine all I want in neutral w/o any noise. I disconnected the prop from the engine and put her in gear - no noise. Boat genius says it needs the drag of the prop. We finally had to vacate our borrowed mooring so we motored about 2 hrs to my harbor. Engine misfiring or backfiring or something as we went. Could not get above 1500 rpm. Also, RPM's drop about 100 when the noise is made. Motored at about 4 kts. Pulled plugs again. Only #3 is fouled. Cleaned and ran again. Plug now looks oily. All cyl pressure is between 95-100 with #3 being 100. There is also some oily residue in the exhaust pipe near the manifold.
What can cause oil in the cylinder? How else can oil get in except through the valves or rings? Am I looking at pulling a 2 yr old engine?
Here's the issue. It only makes this noise, which now sounds more like a "thump", when in gear and it's intermittent. I can rev the engine all I want in neutral w/o any noise. I disconnected the prop from the engine and put her in gear - no noise. Boat genius says it needs the drag of the prop. We finally had to vacate our borrowed mooring so we motored about 2 hrs to my harbor. Engine misfiring or backfiring or something as we went. Could not get above 1500 rpm. Also, RPM's drop about 100 when the noise is made. Motored at about 4 kts. Pulled plugs again. Only #3 is fouled. Cleaned and ran again. Plug now looks oily. All cyl pressure is between 95-100 with #3 being 100. There is also some oily residue in the exhaust pipe near the manifold.
What can cause oil in the cylinder? How else can oil get in except through the valves or rings? Am I looking at pulling a 2 yr old engine?
Comment