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2000 Mercruiser compression check ??

T

Trav89

New member
Hi, first time post here.
I recently purchased a 2000 Bayliner Cuddy with fresh water cooler 5.0 Merc. Engine runs good, did sea trial etc before purchase. Took boat into local marine shop to get winterized/check over. Had them do a compression check, got a call from the mechanic asking if I planned on keeping the hot or selling it, as two cylinders were low.
The readings are :
180/150/180/150 175/170/175/160

Is this something to be concerned about?? 150 sounds like a decent compression to me. I know it’s more than 10% variance, think it’s like 16% between high and low cylinders, but I don’t know, doesn’t sound terrible to me. What do you guys think? Would you be concerned with these numbers at all? Does it warrant further investigation?
Cheers
 
For a 23 yr old engine I say it is good to go for a few more seasons. How many is anyones guess.

My opinion is once you hit 120-130 psi then its time to do something
 
Thanks for the reply. I’m wondering if the mechanic did a wet test or not either. Maybe I could run some Lucas additives to try and free up rings if that’s maybe the issue? Check compression next year or so at the end of the season?
 
I doubt its stuck rungs, more than likely just wear/cylinder scoring or valve seat wear. You most likely have no idea if it ever overheated.

Depending hours of use in a season, check compression every couple years.
 
Thanks for the feedback and replies, much appreciated. I’ll just run it as planned and when the time comes maybe drop a new 350 crate in.
I like the boat, got it for a decent price. Changing out the carpet this winter and some other interior improvements, when the time comes ill plan for a re-power. Thanks again, cheers.
 
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