Just did compression test on Johnson 1995 Ocean Runner....results bad news?? HELP!!

[boater83]

I just finished compression test. Looking at the motor from standing behind the boat, top left is 60 psi, top right is 120 psi, bottom right is 120psi,

Any help would be greatly appreciated. What should I try to do next/repair? Was going to take boat out right now but hesitant. It still starts right up with no issues.

 

[GA_Boater]

Re: Just did compression test on Johnson 1995 Ocean Runner....results bad news?? HEL

After the muff incident and the low number on one cylinder, it might be best to see what is wrong with that cylinder before taking the boat out. You could be turning a not so expensive repair into a really expensive repair. But you won't know until you open it up.

 

[boater83]

Re: Just did compression test on Johnson 1995 Ocean Runner....results bad news?? HEL

Right now I am hoping it is just a bad head gasket. I haven't worked with marine engines before , car yes, but any guidelines on how to remove the head gasket? I recently ordered a used OUTBOARD MARINE CORPORATION for this engine on Ebay, so it will be coming next week.

Circled is the bad PSI port. Is the head gasket on that side or in the middle of the engine? Thanks all.

 

[boater83]

Re: Just did compression test on Johnson 1995 Ocean Runner....results bad news?? HEL

Just took off head gasket for left side of engine...no gasket?? I didn't see any metal shim or anything. Is that normal? I was expecting a shim gasket or something when I opened it, unless I am doing something wrong.


View attachment 102089

 

[windsoreight]

Re: Just did compression test on Johnson 1995 Ocean Runner....results bad news?? HEL

Looks like the gasket is stuck to the block to me.

 

[boobie]

Re: Just did compression test on Johnson 1995 Ocean Runner....results bad news?? HEL

That mtr didn't have head gaskets. The oring acted as a water seal. I'd look real closely at the cyl that had the low compression for any piston scuffing/stuck rings and ect.

 

[SparkieBoat]

Re: Just did compression test on Johnson 1995 Ocean Runner....results bad news?? HEL

yes the boobie is correct, o-rings are head seals. get some new ones. inspect cylinder good for damage, tilt motor up and pour some sea foam in that cyl. let it set over night. paint looks ok on head, also usually from over heat top cyl goes out. I think you got a sticky ring, sea foam should help with that.

 

[boater83]

Re: Just did compression test on Johnson 1995 Ocean Runner....results bad news?? HEL

I'll try pouring some seafoam into that cylinder and order two new orings.

Found site that sells custom cylinder sleeve for our Johnson. Any idea which one I need from the list since Johnson only sells whole block replacement.

 

[Monte1961]

Re: Just did compression test on Johnson 1995 Ocean Runner....results bad news?? HEL

Draw file the head and check for high/low spots. On a flat piece of glass on your workbench and some 220 grit sandpaper. Work head back and forth a few times and then check for deviations. Just remove enough to make flat. Good luck and post results.

 

[boater83]

Re: Just did compression test on Johnson 1995 Ocean Runner....results bad news?? HEL

Not sure what you mean? Are you saying to sand down the piston head a bit ?

 

[SparkieBoat]

Re: Just did compression test on Johnson 1995 Ocean Runner....results bad news?? HEL

that is the way to do it with the 90 degree motors, you usually do not have much warpage on the 60 degree motors, you can still have the head resurfaced, but I do not think that is your problem. I am wondering what caused the scoring. use the sea foam, then replace the seals and reinstall the head and see what you have, be sure to run the motor to operating temp, it will smoke some extra for a little while after the sea foam.

 

[boomer2001]

Re: Just did compression test on Johnson 1995 Ocean Runner....results bad news?? HEL

you can hone the inside of the cyclinder and put new piston and rings, you can get a honing tool that attaches to a drill and do this. No sleeve needed. I have done to my merks and great success.

 

[boater83]

Re: Just did compression test on Johnson 1995 Ocean Runner....results bad news?? HEL

you can hone the inside of the cyclinder and put new piston and rings, you can get a honing tool that attaches to a drill and do this. No sleeve needed. I have done to my merks and great success.

Did you take off the head to hone it. Also will u need a bigger sized piston?

 

[boobie]

Re: Just did compression test on Johnson 1995 Ocean Runner....results bad news?? HEL

Get the mtr repaired correctly now. Running it the way it is can cause you some Bigger problems down the road.