502 Catastrophic Failure!!! Why does this happen?
07-01-2014, 09:54 PM
#21
Registered
Lowering the idle down to 750 could certainly cause reversion if it was on the edge. The lower the idle, the more possibility for reversion. It sounds like it may have had some water in it when you tried to start it and it killed the starter. It's also possible that it bent a connecting rod. Once it killed one rod bearing, then the other one on that journal doesn't have a chance, You are then putting metal through the oil system, which can cause others to go. Were the tops of the pistons clean, like they had been steam cleaned? That is an indicator of water
Eddie
Eddie
07-01-2014, 10:00 PM
#22
Exhaust is about 6 inches above water line when not running, yes external flappers. Water did not come back up the exhaust from outside the boat. My only other question which I have been avoiding is this.....zz502 GM performance cam is what I found in this engine when I tore it down. Not real big. .527/.544 duration at .050 in. for intake is 224 and 234 for exhaust with 110 LSA.
The boat had Stainless marine exhaust with standard risers (about as long as stock mercruiser). With the 110 LSA could it pull enough water back to do this if that was happening?
Again, 200 hours on these engines. So it has been fine for a while. The only thing I changed was lowered idle from 1000 to 750 and all of a sudden I have problems.
The boat had Stainless marine exhaust with standard risers (about as long as stock mercruiser). With the 110 LSA could it pull enough water back to do this if that was happening?
Again, 200 hours on these engines. So it has been fine for a while. The only thing I changed was lowered idle from 1000 to 750 and all of a sudden I have problems.
07-01-2014, 10:10 PM
#24
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Is it the same motor that was the subject of this thread?
http://www.offshoreonly.com/forums/g...-pressure.html
http://www.offshoreonly.com/forums/g...-pressure.html
Good csi !
Where is the nutkick smiley when you need it ?
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07-01-2014, 10:25 PM
#26
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The boat ran great last year, this year first time out ran a little funny. Then was hard to start. Then wiped out the starter. Thought I had bad gas or something, added water zorb and it seemed to be running really well again.
3rd time in the water and after taking a swim break we decided to end the day with a little cruise. Ran it up to about 4900 rpm, no trim yet or anything, temp was good, oil pressure good, then pop bang smoke, not running!
Could bad fuel do this? I am just at a loss for what happened.
3rd time in the water and after taking a swim break we decided to end the day with a little cruise. Ran it up to about 4900 rpm, no trim yet or anything, temp was good, oil pressure good, then pop bang smoke, not running!
Could bad fuel do this? I am just at a loss for what happened.
07-01-2014, 10:45 PM
#30
Charter Member # 55
Charter Member
IMO, not likely. I've had water in my fuel before. Water filled up the water sep filter and then engine would not run. Had to dump the filter abut 3x to get all the water out.
