8hp Milky Spark Plug

[Bonger6]

Hey team - first time to the forum but figured I’d throw a few questions out on my 1989 8hp Evinrude.

I had it out recently and it was a running perfect - full power, good trolling, etc. Halfway through the day I went to take off for home and half power. Tried a few fuel tricks - it would idle and run up to half well -
that’s all. Got home and pulled plugs and my bottom cylinder was milky and literally when I yanked her a few times it spit out fluid which when inspected seems to be water/fuel mix since it’s definitely not straight fuel from simple a fouled plug.

I brought her home in the barrel and just to test the fuel for water tried another tank - same result. Plus water in fuel I would suspect both plugs to be more like that.

I’m figuring head gasket (new impeller last summer and it has always pissed out good water pressure so I don’t think it overheated). I checked compression and I’ve got 100-105 bang on both cylinders still.

So is it possible that the I’ve got a blown gasket just on the second cylinder slightly enough to let water past and foul out/not run but still keep good compression?? Like when I try to put the throttle to her I get a little bypass which will kill cylinder two from firing or have poor firing resulting in my half power situation?? Or maybe it’s not even firing at all and I’m just running on number one. (Also did new plugs with same results)

Either way the head is coming off just as routine maintenance but I’m wondering if because I’ve got good compression I should be looking somewhere else for a water leak source.

Thanks guys!!

 

[TrueNorthist]

Is it salt or fresh? I've seen thermostats and water jacket passages plugged solid with salt but the tell tale kept on working normal. Is deep blue paint right? Might show some darkening or flaking if it overheated.

 

[F_R]

If it isn't a blown head gasket, it is a leaking exhaust cover gasket,, or a pin hole in exh baffle plate, #29 (most likely)

 

[Bonger6]

TrueNorthist it’s a freshwater motor and I’m pretty certain it didn’t overheat - there’s no signs of any degradation on the paint/etc as it looks like brand new. The impeller was near new and all seemed to be working since I had run it in the barrel for a while and could touch everything by hand. Not to say it couldn’t have failed on the water but I don’t believe so.

I’ll go ahead and yank the head regardless to do the gasket and take a look at the exhaust cover gasket as a start. Thanks guys

 

[Bonger6]

Just as a follow up...after removing the head it’s looking like a gasket failure. On the bottom cylinder (problematic cylinder), the seal between the cylinder and head definitely looks degraded so maybe was enough to keep compression up, but failed enough to allow some water past = misfire/fouled plug. I’ll replace and we shall see but all else looks to be perfect.