Blown head gasket Maybe?'

[chopperguy]

Hi, new to the forum, but not to boats. I have a 2000 Johnson 130 (J130PLSSS) outboard. Runs great. I have been periodically pulling the spark plugs to check the condition (installed new ones just a month ago). It's a V4 and the the lower right cylinder (viewed from behind) is what's bugging me. The plug looks different from the rest. It had little moisture beads on the electrode and the thread part was very clean. Ran a compression check on all four cylinders with the following results 120, 120, 125, 115. Of course the 115 is the cylinder in question. The funny thing is, the engine runs great. Not sure if I should quit using it and change the head gasket, I don't want to damage it anymore. Lower right plug in picture is one in question. Cannot see the moisture it evaporated.

 

[oldcatamount]

Re: Blown head gasket Maybe?'

It's not that hard to replace the head gasket. Personally I wouldn't risk further damage and change it.

 

[Monte1961]

Re: Blown head gasket Maybe?'

If you have any questions about it, I would pull the head and physically inspect it. Might be a engine saver? Worst case is you will out a few bucks now or a lot later! Post back and let us know how you make out.

 

[chopperguy]

Re: Blown head gasket Maybe?'

Thanks, you were right, easy job. No cylinder scoring. Decarbonized piston head while I was in there. No carbon at all on the head cover. Now I just need torque specs and seq. I should have the gaskets Friday. Also ordered new thermostats for both sides. Surprisingly not a lot of corrosion in water jacket. Previous owner must have atleast flushed it everytime. This motor has been in saltwater its entire life.

 

[Monte1961]

Re: Blown head gasket Maybe?'

Torque spects depends on bolt size. If 3/8" bolt I think it's around 18" to 22" ftlbs. Good Call on removing head! BTW, when tightening bolts. Work from center out! And don't be afraid to use a little oil on threads. Post back and let us know how you make out.