Carbon or Not

[115johnson78]

I have a Johnson 115hp. I compression tested two cylinders on the port side were at 100psi, the star side bottom is 70psi and the top is 40 psi. Runs rough at idle but will wot at 5000 rpms.

 

[another todd]

Re: Carbon or Not

May be a head gasket leaking between the two cylinders. Could also be stuck, carboned up rings, or worn out rings.

 

[tashasdaddy]

Re: Carbon or Not

A decarb is not going to solve that problem. time to pull the cylinder head and investigate. may be a simple as a gasket, may be time for a rebuild. a $20 gasket will tell the story. then you can decide that the gasket fixed it, or to rebuild, or to run it till it completely dies.

 

[115johnson78]

Re: Carbon or Not

Thats what I was thinking but im not a pro. Thanks for all the help and info.
What type of sealant for the new gasket?

 

[wilde1j]

Re: Carbon or Not

None ... install dry.

 

[tashasdaddy]

Re: Carbon or Not

agree

 

[115johnson78]

Re: Carbon or Not

OK Thanks. just wondering why