Corrosion on cylinder wall johnson 9.9

[maineiac5586]

Ok, all good information, thanks, I'll report back once she is up and running fine (hopefully). Stay tuned.

 

[maineiac5586]

So, I got my new head gasket and it has a split between the 2 CYLINDERS like my old one. I guess that's how it is supposed to be. So now I don't know if it was the head gasket causing the low COMPRESSION I guess I'll find out after I put it in (fingers crossed). I'll get to it next week and report back

 

[racerone]

The newer " big bore " block uses a different head gasket.----What part # are you installing on it now ?

 

[maineiac5586]

338222

 

[racerone]

That is the correct gasket.-------I suspect that this motor has scored pistons.

 

[maineiac5586]

Would that be possible and still have perfect looking cylinder walls (can still see the crosshatch)

 

[flyingscott]

Make sure you resurface the head as it will be warped. Did you ever double check the compression with a different gauge.

 

[maineiac5586]

Yes. Same measurement with different guage. Any tips on resurfacing? I put a straight edge across it and it seems flat

 

[oldboat1]

Before reassembly with fresh head gasket, resurface the mating surface using sandpaper on a flat surface (get an equal shine all around). Torque to spec, using circular pattern starting in the center.

200-400 grit wet/dry sandpaper. Wet the back. Some use a piece of glass for a flat surface.

 

[maineiac5586]

Good news. I put a new head gasket on and thermostat. Compression came up to 120 PSI PER CYLINDER. Starts and runs like a beast. Thanks to everyone's input it is good to go.