jeffmyersvt
Recruit
- Joined
- Aug 24, 2008
- Messages
- 2
1985 Chevy block 260hp engine, serial no. 6899558. I just can't get this figured out, and neither can my mechanic. The engine was stalling out after sputtering at 3000 RPM's & higher last year. It would usually take about 10-15 minutes after first running the boat. It would run at very slow speeds fine. My mechanic started with the fuel line, cleaned the filters, replaced the fuel filter. The issue was better as the boat took longer before it would sputter and stall, up to an hour, but the issue was still there. The engine also struggled at idling, sometimes stalling and revving slightly from about 400 RPM's to 800 when in neutral. If there wasn't enough gas given when just moving forward or in reverse, it would often stall. Made it kind of tough when docking, especially in tight spots. I tried turning the idle up a bit, which helped with the stalling but the revving continued and it wasn't the answer as the boat moved too quickly when just in gear. The boat was originally a salt water boat. One exhaust manifold was replaced 4 years ago and the other just done as part of this diagnosis along with the elbow. There was water mixing with the oil in the block as when the cover was taken off, it looked like crisco around it. The bottom of the oil stick appeared to be pure oil however, and the mechanic felt although water had gotten in, it wasn't bad. That led the mechanic to the manifold and elbow. He had to change the oil 4 times after the replacement to make sure the water was out of the block. I've checked it since and it appears to be fine. He also rebuilt the carb as part of this. First time I take the boat out, the idling issue is clearly still there and the boat is stalling out as before at idling or when clicking into gear. Never an issue at the shop as it's not under any load. I ran it for 1/2 hour and it ran fine. Stopped it for about an hour and then ran it again for about an hour and no issues at the higher RPM's. Stopped it for about an hour and then after taking off again, it began to sputter after about 15 minutes. I backed off the throttle to under 2000 rpms and docked the boat. Started it again an hour later, and about 15 minutes after running it at 3000-3200 RPM's it started to sputter. Backed off to 2000 and ran it for another 15-20 minutes and had to back off even more as it sounded like it was struggling. What else could this possibly be. I know my mechanic well and fully trust him. He didn't charge for much of the work done recently because the issue hasn't been solved. He has 25+ years experience on boat engines, but I'm ready to try someone else at this point.
