1995 Johnson 140-scored cylinder

[Michael Healy]

One of the cylinders in my motor has a score that will catch a fingernail. What are the usual causes for this to happen?

Thanks,

Mike

Exact Model: J140TXARC Serial #: G.03661844

 

[k4ubr]

Re: 1995 Johnson 150-scored cylinder

Re: 1995 Johnson 150-scored cylinder

your model number is a little off, but is is a v4 or v6 140 is v4 -150 is v6. as for the score, a bad carb on that hole, there a lot of things that it could be.cooling, or it chipped a ring, to many variables.

 

[Michael Healy]

Re: 1995 Johnson 140-scored cylinder

Hi-Thanks for your response.

Yes I said 150, but it is a 140.

I asked the question because I am trying to determine what might have caused the problem to prevent it in the future, and I am trying to decide what to do about it.

The scores are above the intake port, so I am wondering if it is possible to get a look at the rings to determine if they are still ok. The top of the piston looks good. Maybe I can address the root of the problem without redoing the cylinder??

My plan right now is to inspect as much as possible, replace head gasket, and test compression. If the compression is good (within 10-15% of the other cylinders), clean carbs, make that cylinder run a little richer than the others, and keep on getting up with the scored cylinder.

If cylinder doesn't look good, then re-do that cylinder, piston, rings, etc.

I've heard some say if one cylinder is bad, then all cylinders need to be redone or new head installed. I have also read that redoing 1 cylinder is an approved practice, and there are pistons made for this purpose that are the same spec-weight as the original. ??

One more thing-thermostats looked bad-one was stuck partially closed. I know this was a problem, but since only 1 cylinder is bad, I think the carb may be also be an issue-what do you think?

Thanks,

Mike

 

[Faztbullet]

Re: 1995 Johnson 140-scored cylinder

Your year is off its a 1994. How big a scratch? Is it on port or starboard side? Where is it located in cylinder (example: 2oclock port side)? Could have been trash that went thru cylinder or could be piston ring locating pin backed out(common) due to coking from improper cylinder temp, cheap fuel and oil and bad t-stat or high temp due to weak impeller.

 

[Michael Healy]

Re: 1994 Johnson 140-scored cylinder

Re: 1994 Johnson 140-scored cylinder

Scores are in an area 1 1/2 wide, 3" deep in line with the intake.

Can 1 cyl. be bored, and rebuilt, or do they all have to be redone?

What is approximate cost to do a cylinder? I have heard prices ranging from $200 to $600.

Thanks,

Mike