metriccrescentwrench
Commander
- Joined
- Oct 22, 2007
- Messages
- 2,598
This engine's had multiple issues since I purchased it, and that's made it confusing at times trying to describe the problems and of course trying to diagnose them.
I feel like I may be down to the last problem, however it's kicking my butt. The last two times I've taken the boat to the lake it started up ok, ran fairly decent for 15 or 20 minutes, including some WOT runs, then all of a sudden it won't idle. Once the problem shows up it takes a lot of throttle just to keep it running, it's very rough and bogs very badly coming out of the hole. It seemed to run ok once on plane, but I didn't push it hard (I just wanted to get back to the boat ramp). (I believe this problem has been present since day one, but the other problems I've since fixed have covered it up).
Engine has a new CDI power pack and new CDI timer base. Last week I ran through all the ignition tests spelled out in the OMC factory service manual (AGAIN) and everything checked out ok.
Before the last time we went to the lake I put in new spark plugs, when we got home I checked them and they were all nearly identical, a light brown coloring on the insulator with nothing out of the ordinary.
This weekend I ran the engine at a fast idle for 20 minutes in a tank to get it good and warm (but of course it wouldn't act up for me), then repeated all ignition tests to see if something was degrading with heat - everything still checked out ok. One thing that's got me puzzled though is that after 20 minutes of idling the starboard side spark plugs were all very clean while the port bank plugs were all black. (I don't know if that's a separate issue or not.) I've checked head temperatures with an IR thermometer, they're all at 140 to 150 while idling (exactly where they belong). I put everything back together and after it got dark ran the engine at idle to look for any sparks between a coil or plug wire and ground - nothing.
Last night I re-re-checked timing and link-n-sync, all still good. I looked for any sign of fuel/air mixture spitting out of the carbs in case there was a bad reed, didn't see anything. I tried adjusting the idle screws, but between running in a tank and trying to read the dash mounted tach I decided I wasn't accomplishing anything and put all the idle screws back where they started. After a couple more minutes of idling the engine died, I restarted it and as soon as it came out of fast-start it died again. I restarted and was only able to keep it running with a lot of throttle - just the same as at the lake. By then it was too late to do anything else.
Anybody ever seen anything like this? Any expert opinions are very much appreciated.
I feel like I may be down to the last problem, however it's kicking my butt. The last two times I've taken the boat to the lake it started up ok, ran fairly decent for 15 or 20 minutes, including some WOT runs, then all of a sudden it won't idle. Once the problem shows up it takes a lot of throttle just to keep it running, it's very rough and bogs very badly coming out of the hole. It seemed to run ok once on plane, but I didn't push it hard (I just wanted to get back to the boat ramp). (I believe this problem has been present since day one, but the other problems I've since fixed have covered it up).
Engine has a new CDI power pack and new CDI timer base. Last week I ran through all the ignition tests spelled out in the OMC factory service manual (AGAIN) and everything checked out ok.
Before the last time we went to the lake I put in new spark plugs, when we got home I checked them and they were all nearly identical, a light brown coloring on the insulator with nothing out of the ordinary.
This weekend I ran the engine at a fast idle for 20 minutes in a tank to get it good and warm (but of course it wouldn't act up for me), then repeated all ignition tests to see if something was degrading with heat - everything still checked out ok. One thing that's got me puzzled though is that after 20 minutes of idling the starboard side spark plugs were all very clean while the port bank plugs were all black. (I don't know if that's a separate issue or not.) I've checked head temperatures with an IR thermometer, they're all at 140 to 150 while idling (exactly where they belong). I put everything back together and after it got dark ran the engine at idle to look for any sparks between a coil or plug wire and ground - nothing.
Last night I re-re-checked timing and link-n-sync, all still good. I looked for any sign of fuel/air mixture spitting out of the carbs in case there was a bad reed, didn't see anything. I tried adjusting the idle screws, but between running in a tank and trying to read the dash mounted tach I decided I wasn't accomplishing anything and put all the idle screws back where they started. After a couple more minutes of idling the engine died, I restarted it and as soon as it came out of fast-start it died again. I restarted and was only able to keep it running with a lot of throttle - just the same as at the lake. By then it was too late to do anything else.
Anybody ever seen anything like this? Any expert opinions are very much appreciated.