Foulded Spark Plug

[wayne'o]

During a recent fishing trip I had trouble with my 1995 Johnson 175 miss firing. I checked all the plugs and found # 1 fouled with a dry white substance. The gap wasn't bridged, but the insulator was impacted with this white stuff. I talked to my local marine engine repair guy and he couldn't figure it out. He suggested that I change all the plugs and run it to see what happens. Anyone got any idea's what the white stuff is, and where it came from.

 

[Hooty]

Re: Foulded Spark Plug

Dry,white stuff?<br />That could be some bad juju, like nr.1 might be running real lean, but the mechanic should know what a lean-running plug looks like. The only other thing I could think of is water and that usually "steam cleans" the plug and makes it all shiney and new looking. I wouldn't run the engine until I found out what's wrong.<br /><br />g'luck & c/6<br /><br />Hooty

 

[Dhadley]

Re: Foulded Spark Plug

Sounds like water from the glue seam leak. Fairly common on those motors. It can be fixed. Have your dealer call Precision Manufacturing at 800-237-5947 and talk to Norm or Tom.<br /><br />Good luck!

 

[wayne'o]

Re: Foulded Spark Plug

My partners took the boat out today with new plugs and engine ran fine for about 50 miles. After that it started to miss again. They decided to troll home and egine ran worse and started making a rattling noise. I pulled the #1 plug and it had the same light colored material fouling the plug. We checked the spark and that cylinder doesn't seem to be firing. I think that cylinder is dieseling and the white stuff ( light colored stuff) is oil build up. The rattling noise is from the dieseling. What do you think?

 

[Hooty]

Re: Foulded Spark Plug

Dieseling?<br />You're gonna wish.<br /><br />c/6<br />Hooty

 

[dick]

Re: Foulded Spark Plug

Sounds all bad to me, check the compression.

 

[Joe Reeves]

Re: Foulded Spark Plug

Wayne.... If that "white stuff" is a liquid, you have, in all probability, had a head gasket or exhaust gasket start to leak which would allow water to enter the cylinder.<br /><br />If, on the other hand, that "white stuff" is metal (aluminum), your engine has set up a pre-ignition situation and the piston is deteriorating.

 

[wilde1j]

Re: Foulded Spark Plug

Might be a good time to check the timing.

 

[wayne'o]

Re: Foulded Spark Plug

Well, after a few more tests and another consutation with my mechanic I think we found the problems. The white stuff is dried salt water from a leaking O ring on #1 and the water jacket. Coil for # 1 doesn't test out good with ohm meter, but we had spark when engine was cold. I think coil is breaking down when it gets hot. <br /> Pulled head off last night and the corrosion on the head and block looks like it would be hard to remove and reseal. Not sure what the best way to clean and reseal would be. Any idea's?