1998 250 Johnson Compression

[HYDRASPORT84]

I just checked the compression on my Oceanrunner, below are the results.Is this motor still within specification or due for a rebuild??<br /><br />100 102<br />100 102<br />90 95

 

[WillyBWright]

Re: 1998 250 Johnson Compression

90 to 102, 12psi min to max. Try a decarb, but I'm not worried.

 

[HYDRASPORT84]

Re: 1998 250 Johnson Compression

bump

 

[R.Johnson]

Re: 1998 250 Johnson Compression

I would take the head off an look. Save's time, and in most case's, lot's of money.

 

[Dhadley]

Re: 1998 250 Johnson Compression

Like Willy said, that's fine but it seems if you're still worried. Go ahead and pop the heads off and look. The heads on those motors have "progressive" chambers. The top should be the highest, middle slightly less and the bottom slightly less again (the bottom runs the highest combustion temps so it has the deepest pocket). <br /><br />You're well within the spec of 15 lbs high to low. And on those motors the one side will usually be slightly higher than the other. Yours are very consistant side to side.

 

[HYDRASPORT84]

Re: 1998 250 Johnson Compression

What would I be looking for if I pulled the heads off,damaged cylinder walls??