jamesdgreen2016
Petty Officer 3rd Class
- Joined
- Aug 26, 2016
- Messages
- 78
I have a 1992 Sea Ray with a V6 Mercruiser inboard engine on there. It's been largely rebuilt with a lot of new parts but I don't know exactly which ones. The problem WAS: take boat out, runs great for an hour, casual boating - some booting around at top speed and some slow cruising, some tubing, whatever. Runs great. Then after about an hour if you try and go top speed started popping or backfiring through the carb and lost power, but if you slowed it down it would still cruise alone just slowly. Then if you did this for about 15 minutes more it would die (like running out of gas only there was still gas). Stall. Then no start condition for a while. I didnt try and start it again until the next morning when it fired back up and ran great for an hour again and then started popping and backfiring through the carb and losing power at high speed. I didnt wait around for it to stall out but I assume it would have come next. Then we took boat out a few more days and the same thing - rock and roll for an hour then popping backfire through carb and loss of power. Reliably every time after 60 min of good boating at all speeds the problem would occur. Never before. Very reliable.
So I came on here and a few other sites and found people had similar things happen with their boats and discovered it was the ignition coil and / or the ignition module overheating and malfunctioning causing all those symptoms. SO I replaced the ignition coil because it was cheaper.
Then we went out twice for about an hour and no popping or backfiring or anything. It was beautiful. Of course I sort of felt like if I started pushing it after the hour we were out the problem might still resurface.
Then the 3rd time we went out we were out for an hour without a problem. We stopped the boat in the middle of the lake and sat there for a while, then tried to start it back up - no start. Waiting ten minutes and tried again - put throttle all the way down thinking maybe it was flooded or something and it managed to start up so we drove in.
This time we let the boat sit for half an hour then we went back out.
Did some tubing (pushed the engine a bit) and it started LOSING SOME POWER but not like before, less than before the ignition coil was changed - and NO POPPING OR BACKFIRING THROUGH THE CARB ANYMORE.
Just loss of some power but still fast enough to tube, and zero popping sounds or backfires.
SO THERE WAS IMPROVEMENT BY CHANGING THE IGNITION COIL it seems.
I had like 5 kids tube in a row there and had cut the engine like 4 times during the last half hour to let each on board with no problem starting. But on that last kids tubing run I was noticing the loss of power issue a bit more even though again it wasnt as before where I couldnt make the boat go fast, it was just having a harder time than it had been when we got started tubing. Anyway after that last kid got on the boat - NO START.
So we figured it needed to cool off and we let the kids swim and sit around for 20 or 30 min and then I managed to get the engine started again like I had earlier.
Note: The engine does not appear to be overheating.
After we got it started we drove (fast again, it seemed to get power back) in to shore and I havent boated since (will be tomorrow). When we got to shore, I was able to cut the engine and restart it 5 times in a row with no problem. And with he muffs in the driveway I have been able to cut and restart it no problem a bunch of times today.
MAIN QUESTION: Given that the ignition coil replacement solved the backfire popping through the carb thing, apparently solved the stalling out of the blue while cruising thing, and apparently resulted in less loss of power when the loss of power thing does occur, is it reasonable to conclude the rest of the fix is to swap that Thunderbolt IV ignition module out for a new one, or is that too much of a leap?
FOLLOW UP QUESTION: Unrelated but why not ask now - when I make a really sharp turn at slow speeds in this boat I notice a (not loud or bad sounding but audible) sound that I could describe as a clicking slight grind in time with the prop spinning. Like rhythmic. It is silent when not turned to the max on left or right, but then you can hear it when making sharp turns. Ive read u joints perhaps? Is this something I can let wait until next season and anybody know what type of cost its gonna be? Or if its a problem I need to deal with?
So I came on here and a few other sites and found people had similar things happen with their boats and discovered it was the ignition coil and / or the ignition module overheating and malfunctioning causing all those symptoms. SO I replaced the ignition coil because it was cheaper.
Then we went out twice for about an hour and no popping or backfiring or anything. It was beautiful. Of course I sort of felt like if I started pushing it after the hour we were out the problem might still resurface.
Then the 3rd time we went out we were out for an hour without a problem. We stopped the boat in the middle of the lake and sat there for a while, then tried to start it back up - no start. Waiting ten minutes and tried again - put throttle all the way down thinking maybe it was flooded or something and it managed to start up so we drove in.
This time we let the boat sit for half an hour then we went back out.
Did some tubing (pushed the engine a bit) and it started LOSING SOME POWER but not like before, less than before the ignition coil was changed - and NO POPPING OR BACKFIRING THROUGH THE CARB ANYMORE.
Just loss of some power but still fast enough to tube, and zero popping sounds or backfires.
SO THERE WAS IMPROVEMENT BY CHANGING THE IGNITION COIL it seems.
I had like 5 kids tube in a row there and had cut the engine like 4 times during the last half hour to let each on board with no problem starting. But on that last kids tubing run I was noticing the loss of power issue a bit more even though again it wasnt as before where I couldnt make the boat go fast, it was just having a harder time than it had been when we got started tubing. Anyway after that last kid got on the boat - NO START.
So we figured it needed to cool off and we let the kids swim and sit around for 20 or 30 min and then I managed to get the engine started again like I had earlier.
Note: The engine does not appear to be overheating.
After we got it started we drove (fast again, it seemed to get power back) in to shore and I havent boated since (will be tomorrow). When we got to shore, I was able to cut the engine and restart it 5 times in a row with no problem. And with he muffs in the driveway I have been able to cut and restart it no problem a bunch of times today.
MAIN QUESTION: Given that the ignition coil replacement solved the backfire popping through the carb thing, apparently solved the stalling out of the blue while cruising thing, and apparently resulted in less loss of power when the loss of power thing does occur, is it reasonable to conclude the rest of the fix is to swap that Thunderbolt IV ignition module out for a new one, or is that too much of a leap?
FOLLOW UP QUESTION: Unrelated but why not ask now - when I make a really sharp turn at slow speeds in this boat I notice a (not loud or bad sounding but audible) sound that I could describe as a clicking slight grind in time with the prop spinning. Like rhythmic. It is silent when not turned to the max on left or right, but then you can hear it when making sharp turns. Ive read u joints perhaps? Is this something I can let wait until next season and anybody know what type of cost its gonna be? Or if its a problem I need to deal with?
