J90 wet plug Cyl 1

[Steve2603]

Last week I ran a full decarb on my 1984 J90, then ran a compression test with all 4 cylinders showing between 120 & 125psi. I then fitted a new set of plugs and took the boat out yesterday for a spin.. Top end speed was a little off so back at home I checked the plugs to find the plug in Cyl 1 looking like new and wet.. I'll check the coil/spark today but am not sure why the plug is wet or how water could get in there if the compression tested ok. There was only a small amount of water on the plug did not look of feel like the cylinder was flooded. any idea's?

 

[JB]

Re: J90 wet plug Cyl 1

That water could have come from the fuel tank, filter, fuel pump, carb, or crankcase without affecting the compression, Steve. Carb or crankcase are most likely.

 

[Steve2603]

Re: J90 wet plug Cyl 1

I have a sierra water/fuel seperator on the boat and it shows no signs of water in the glass so guess it's the crankcase.. also no sign of water in any of the other cylinders so guess that rules out the carb's/fuel pump..

 

[lostinboat]

Re: J90 wet plug Cyl 1

I have a 83 J90,I found a small trace of water on my #4 plug. Compression was great, what I found was water sweeping passed the head gasket. the gasket wasn't blown but was getting ready to blow. replaced both head gaskets and no more water and motor runs better now than ever before.Just my 2cents.hope it helps

 

[Steve2603]

Re: J90 wet plug Cyl 1

Thanks, Plan to remove the head as soon as my local dealer gets new gaskets in stock...