Ok, this problem is going to be difficult to explain but here goes. Ever since I bought this boat (about 5 yrs ago) the engine would sometimes start misfiring if I pushed it up into the 5000 rpm range, like the power pack is cutting fire to all cylinders to limit rpm. It is an intermittent problem and since I usually cruise at around 3500 rpm anyway it didn't bother me that much. I had the boat out this past weekend and was cruising along at around 3000 rpm and it started doing this again. Before I knew it, it was doing it around 1200 rpm and would sometimes just die completely. If I let the engine sit for a few minutes I could start it back up and it would go for a while at low rpm but would eventually start doing it again. It really feels like it's electrical since it cuts out at a regular frequency like a rev-limiter would do. No warning horn (horn does work) and it's not doing it at 2500 like SLOW mode would, it's just all over the place. I limped it back to the dock and took it out the next day. I ran it around for about 10 minutes and it did fine at ALL rpms. I was planning to just replace the power pack but I figured I'd post here first to get ideas. What's frustrating is since I can't replicate the problem now, it's going to be hard to tell if any new parts fixed the problem.
It seems like it could be temperature related since it was about 102 degrees that day and only 85 the next day, but the tell-tale was streaming water fine and I felt the cylinders the day it was doing this and they were hot but not scorching. I don't know how hot they're supposed to be. I unhooked the starboard side temp sensor after calling my mechanic, and the problem was still there, but stupidly I didn't realize there was a port side sensor too and never unhooked that one, duh!! I'm embarrassed to even admit that one.
It seems like it could be temperature related since it was about 102 degrees that day and only 85 the next day, but the tell-tale was streaming water fine and I felt the cylinders the day it was doing this and they were hot but not scorching. I don't know how hot they're supposed to be. I unhooked the starboard side temp sensor after calling my mechanic, and the problem was still there, but stupidly I didn't realize there was a port side sensor too and never unhooked that one, duh!! I'm embarrassed to even admit that one.
Unhooked both temperature sensors and it made no difference.