2 stroke @ 60 psi upper and 150 psi lower

J

jayard78

Petty Officer 2nd Class
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Dec 28, 2008
Messages
101
I recently did a compression check after a month w/o one and I found that a cylinder that was at 160 psi was now at 60 psi and the other one dropped from 160 psi to 150psi. This is an old 1980 40hp motor and I am wondering if I do a decarb if this may fix the compression a little? I wanted to try simple stuff before going ahead with a rebuild. Anyone ever have a success stories about a similar situation?
 
tashasdaddy

tashasdaddy

Honorary Moderator Emeritus
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Nov 11, 2005
Messages
51,019
Re: 2 stroke @ 60 psi upper and 150 psi lower

never hurts to try it. could be a cheap fix. but with 100 psi drop, i doubt it will work. time to pull the head, and see if you have a blown head gasket or worse.
 
J

jayard78

Petty Officer 2nd Class
Joined
Dec 28, 2008
Messages
101
Re: 2 stroke @ 60 psi upper and 150 psi lower

What do you mean by pull the head? Where is the head gasket located on an outboard? I have a shop manual but it just shows the complete disassembly of the powerhead and I am unsure if I can replace the gasket w/o removing the powerhead from the unit.
 
E

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: 2 stroke @ 60 psi upper and 150 psi lower

Use the BRP parts catalog for your specific model to locate and name the parts of your engine. The spark plugs are in the cylinder head. The cylinder head gasket is between the cylinder head and the crankcase or engine block.
http://epc.brp.com/default.aspx?brands=ej&lang=e

You have too much lost compression for a complete de-carbon treatment, probably a blown cylinder head gasket.
 
F

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,195
Re: 2 stroke @ 60 psi upper and 150 psi lower

Or worse. You will know when you get the head off.
 
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