Spark Plug question..

[*WEAVER*]

I have a 2 stroke 79 mercury 80 horse 4 cylinder. I have been having problems getting this thing to run. I took the spark plugs out today, 2 of the plugs were clean as could be almost looked new, 2 of them were very black. Any ideas of what might be happening here? I run seafoam in my gas, I dunno if that has anything to do with it. Just curious. Thanks

 

[skillman]

Re: Spark Plug question..

Sounds like it isnt firing, or could have a blown head gasket letting some water get into the cylinders, if the plugs look like they been steamed cleaned water is the culprit! My advice, do a compression check on those cylinders and compare to the other 2.

 

[Scaaty]

Re: Spark Plug question..

Yeah, got a feeling ya got a water leak..

 

[*WEAVER*]

Re: Spark Plug question..

Now that I get to thinking about it, you guys are probably right. The 2 dirty plugs have some rust buildup on the metal, I'm guessing that is probably water getting to them. I dunno, I've had problems with this thing ever since I got it, I guess it's time to part it out. It's on a bass boat that I payed $2500 for. Maybe I can get some money back at least on some parts. I can do the simpler repairs on these things, but getting into the pistons and stuff don't wanna mess with it.

 

[Scaaty]

Re: Spark Plug question..

Lots of good parts there, and will fetch bux on ebay..