1958 johnson sea horse low compression

[mntboy]

My 58 seahorse has been running good but has started losing power at full throttle checked compression and top cylinder had 123 psi bottom 72 psi(checked with electric start) Is this an easy fix?

 

[R.Johnson]

Re: 1958 johnson sea horse low compression

could be just a head gasket, take the head off.

 

[mntboy]

Re: 1958 johnson sea horse low compression

Can i make a new head gasket or will i need to buy 1?

 

[R.Johnson]

Re: 1958 johnson sea horse low compression

Buy one.

 

[mntboy]

Re: 1958 johnson sea horse low compression

Thanks

 

[Monte1961]

Re: 1958 johnson sea horse low compression

while head is off, look to see if there is pit marks in or on, head and piston. Check for speed marks on cylinder walls. But with the top being 123lbs, I would bet if lower cylinder looks good then bad head-gasket. post back what you find!

 

[mntboy]

Re: 1958 johnson sea horse low compression

while head is off, look to see if there is pit marks in or on, head and piston. Check for speed marks on cylinder walls. But with the top being 123lbs, I would bet if lower cylinder looks good then bad head-gasket. post back what you find!

Haven't took it off yet but I will when i get a new gasket. How tight should bolts be that hold head on? I found that mine where not all that tight, Could this have been the probleme?