crankcase pressure

arhall

Cadet
Joined
Jun 6, 2003
Messages
7
I have low compression on one cylinder (60psi)and rings and cylinder walls look ok. I was told that a leak in the crankcase could cause this. How do I check for a leak in the crankcase?
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: crankcase pressure

You were told wrong, Badwrench. <br /><br />Crankcase compression/vacuum has little to do with cylinder compression.<br /><br />If you have 60 psi on one cylinder, it has to do with the sealing of the cylinder: gasket, rings, etc.<br /><br />Good luck. :)
 

jim dozier

Lieutenant Commander
Joined
Jan 8, 2003
Messages
1,970
Re: crankcase pressure

Even if the cylinder and rings "look" OK they could be worn to the point where they aren't sealing well or perhaps the cylinder is out of round. Have you had them out or just looking in from the top? Have you decarbed?
 

adam171771

Cadet
Joined
Jun 9, 2003
Messages
26
Re: crankcase pressure

If there is no evidence of scoring, I would definetly try the decarb first as ring could be sticking from carb buildup in the grooves
 

arhall

Cadet
Joined
Jun 6, 2003
Messages
7
Re: crankcase pressure

I removed the piston for inspection but the rings were not stuck and no obvious scoring on piston or cylinder wall.Maybe the head gasket was leaking.I didn't use any gasket sealer on the head gaskets.What gaskets on an 87 evinrude 200 require sealer?
 

Hooty

Rear Admiral
Joined
Oct 2, 2001
Messages
4,496
Re: crankcase pressure

Don' know about your '87 200, but the manual sez to use OMC Gasket Sealing Compound on my '76 200. What does your manual say?<br /><br />c/6<br /><br />Hooty
 
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