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650 compression woes
- Thread starter seadoobie
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I'm not familar with a 650 could it be a 657? Is this in a boat? If you could give us more info. year, model, we could help you more.
I'm not sure whats causing the 240-250psi, but before you tear the engine down I think I would recheck the compression with another guage.
I'm not sure whats causing the 240-250psi, but before you tear the engine down I think I would recheck the compression with another guage.
seadoobie
New Member
ok so its a 95 seadoo speedster boat & the engine is in it and does have twin 657's.
(i just call them 650's by habit) I also tested all 4 cylinders a few times to make sure it wasnt a fluke. 1 thing about that cylinder is, when i do have the gauge in it , it takes about everything the battery has to turn that 1 cyl. over. None of the others have that problem.
From what i know about this boat, both engines were rebuilt about 2 years ago, they were started and ran awhile before the owner winterized and stored it for 2 years.
(i just call them 650's by habit) I also tested all 4 cylinders a few times to make sure it wasnt a fluke. 1 thing about that cylinder is, when i do have the gauge in it , it takes about everything the battery has to turn that 1 cyl. over. None of the others have that problem.
From what i know about this boat, both engines were rebuilt about 2 years ago, they were started and ran awhile before the owner winterized and stored it for 2 years.
It's probably going to take someone smarter than me to figure this out, my guess would be the rotary valve. I can't figure out why one cylinder would be that high and the other normal. If you release the compression, ie remove the spark plug on the cyl. with the high compression, will the motor turn over normally? Disconnect both plugs and turn the motor with the battery.
Lou
Lou
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