M50d2 compression test results

Raymgle

Recruit
Joined
Oct 5, 2009
Messages
3
Top 115psi mid 115psi Bottom 130psi
Is this range ok or do i have a problem.??
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: M50d2 compression test results

Ahoy! and welcome to iboats. :)

I would call that okay, Ray. You might try a decarbonizing treatment to bring the range in a bit, but 15% or less is acceptable in most books and yours is below 15%.
 

Raymgle

Recruit
Joined
Oct 5, 2009
Messages
3
Re: M50d2 compression test results

Hi JB
I should have said that them readings were when the engine was hot.
I redid them when the engine was cold .Slight improvement
Top 120psi Mid 120psi Bott 135psi.
Why would they be better when cold????:
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: M50d2 compression test results

There could be a half dozen things that were different besides being cold, Ray. Even differences in air temp can cause a shift in psi.

Don't think of the cold readings as better. They aren't, they are just different.
 
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