140hp mercruiser. Keeps blowing head gasket

Shawn168

Cadet
Joined
Aug 6, 2013
Messages
12
1985 140hp. Keeps blowing the outter edge of the head gasket under the manifold. Very small, but you can hear it. Replaced it 2 times, same spot every time. #1 145 #2 140 #3 180 #4 145 on compression test after the gasket gets replaced. Wtf?!?!? Smooth surface on block and head, .003-.004 gap. I did recently put in an electronic conversion and new 40,000 volt, 1.5 ohm coil. Nothing else has been changed. Valve adjustment needed? I'm stumped
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,093
Re: 140hp mercruiser. Keeps blowing head gasket

drop the initial timing to 0 or 1 BTDC
 

Shawn168

Cadet
Joined
Aug 6, 2013
Messages
12
Re: 140hp mercruiser. Keeps blowing head gasket

It's blowing out by cyl #3 by the way
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,093
Re: 140hp mercruiser. Keeps blowing head gasket

are you using the correct pattern when torquing the head bolts, are you running a tap thru the holes to clean them first.
 
Top