Sherlock_Holmes
Recruit
- Joined
- Apr 26, 2011
- Messages
- 2
Well, I've been reading posts on here until I'm almost cross eyed. I've got a 1985 Cobia Ski Boat with a Mercruiser 470 (3.7 liter 4 cylinder). I bought the boat about a month ago and the previous owner that had knowledge of the boat is deceased and his family sold the boat.
I took it to a mechaninc to give it a once over to work out any kinks he may notice. He changed the oil, put in new plugs, new anti-siphon valve on the fuel tank, checked the the fuel quality (tank was left 3/4 full from last year), and I added a can of Sea Foam and then 8 more galons fresh fuel.
I took it to the lake and cruised about 3 miles at full speed and slowed down to a little above idle and the boat cut off. I tried to re-crank it and it would barely turn over like the battery was dead. I put in my back up battery, a fully charged high amp marine battery, and it did the same thing. Once the motor cooled it turned over normally but did not run smooth and back fired. Needless to say, my whole family was stranded in the middle of the lake for about 4 hours.
I took it back to the mechanic and he said that the high amp battery I was using had burned up the starter so he had it rebuilt. He also put on a new distributor cap due to a small crack. Also changed the rubber water pump (impeller) in the foot due to it missing 2 blades.
I took it back to the lake again and I ran ir for about a mile or so and it started back firing again after it got hot and I thankfully made it back to the dock. I turned it off and tried to re-crank and it was like the battery was dead just like before. After it cooled for about 90 minutes it spun over good and cranked but still back fired. Also, I was able to idle it up in neutral but it bogged down if I tried to idle it up in drive.
At this point, I don't know if I should burn it, sink it, or try to fix it myself.
I am thinking it may be in the timing or coil. I talked to another mechaninc who said it has an aluminum block and that the 470's have always been hard to turn over when hot because the block swells. He suggested I buy a switch to hook up 2 batteries at once to crank when its hot.
I talked to yet another mechanic, and he said if it isn't in the timing then it's the starter. But, the starter is freshly rebuilt. I know it could still be a bad starter but I just think it is something else.
Any ideas before I have a nervous breakdown? I've got 2 anxious little boy wanting to go tubing instead of watching daddy paddle.
I took it to a mechaninc to give it a once over to work out any kinks he may notice. He changed the oil, put in new plugs, new anti-siphon valve on the fuel tank, checked the the fuel quality (tank was left 3/4 full from last year), and I added a can of Sea Foam and then 8 more galons fresh fuel.
I took it to the lake and cruised about 3 miles at full speed and slowed down to a little above idle and the boat cut off. I tried to re-crank it and it would barely turn over like the battery was dead. I put in my back up battery, a fully charged high amp marine battery, and it did the same thing. Once the motor cooled it turned over normally but did not run smooth and back fired. Needless to say, my whole family was stranded in the middle of the lake for about 4 hours.
I took it back to the mechanic and he said that the high amp battery I was using had burned up the starter so he had it rebuilt. He also put on a new distributor cap due to a small crack. Also changed the rubber water pump (impeller) in the foot due to it missing 2 blades.
I took it back to the lake again and I ran ir for about a mile or so and it started back firing again after it got hot and I thankfully made it back to the dock. I turned it off and tried to re-crank and it was like the battery was dead just like before. After it cooled for about 90 minutes it spun over good and cranked but still back fired. Also, I was able to idle it up in neutral but it bogged down if I tried to idle it up in drive.
At this point, I don't know if I should burn it, sink it, or try to fix it myself.
I am thinking it may be in the timing or coil. I talked to another mechaninc who said it has an aluminum block and that the 470's have always been hard to turn over when hot because the block swells. He suggested I buy a switch to hook up 2 batteries at once to crank when its hot.
I talked to yet another mechanic, and he said if it isn't in the timing then it's the starter. But, the starter is freshly rebuilt. I know it could still be a bad starter but I just think it is something else.
Any ideas before I have a nervous breakdown? I've got 2 anxious little boy wanting to go tubing instead of watching daddy paddle.
