Mercury 85hp has bad miss.

[jsfpilot2b]

I have just purchased a 1988 Bayliner with a mercury 80hp. Took it to the lake today and it has a bad miss. One cylinder is not firing. It tries to fire but just bogs itself down at higher RPM's. I ran it today at the lake for about an hour and a half thinking it might work itself out but it didn't. Top speed with miss, 20mph. I know the boat has been parked for at least a year. There was some gas in the tank. I added premium gas to it and the right amount of oil. I pulled the plugs. One plug was black and wet with fuel, the other two were dry and almost white. I was wondering if the plugs could be bad?<br /> Please help!

 

[steelespike]

Re: Mercury 85hp has bad miss.

I think its pretty obvious one plug isnt firing.<br /> Clean it and switch it with one of the others.<br /> On some motors you can switch the coils to see <br />if one is bad.