Water/wet spark plugs HELP ASAP!!!

[Mike(nj)]

Leaving for the shore tomorrow with the boat........Traded my good running 9.9 for this 1992 25hp Mercury just a few days ago. Motor starts on 1st pull. 1st day I took the water pump apart as it was hardly pumping water out the tell tail. Pump is like new so put it all back together. I then checked the thermostat and it frozen closed so I just took it out and put it back together. Tell tail pumps excellent now.

Bought some new NGK plugs(gap @ .040) as the old ones were original! Ran it for a bit and rechecked them. They look like water spots and oily!? The old plugs were nice and dry. Did a compression test and got 120 psi in each cyl.

Only other change was I combined both tanks of fuel into 1(ccame with 2 tank and both had fuel in them). Could it be the other tanks fuel was so old its not firing right?! I mean it idles and runs great even with the plugs being wet.

HELP!!!!

 

[MarshMan73]

Re: Water/wet spark plugs HELP ASAP!!!

Do yourself a favor now and put a new thermostat in it before you go out in it. The thermostat is there for a reason. I'm not 100% sure about this, but I believe if you run it like that for long the cylinder doesn't expand like it should if it were warmer and will cause premature wear on the cylinder wall. Also makes it run like crap because it's too cold. Could have a cracked baffle plate or bad gasket, or could just be too much pressure on the hose while running? Running it with a new thermostat in and in the water will tell for sure.

 

[sschefer]

Re: Water/wet spark plugs HELP ASAP!!!

Ace advice about the thermostat, put it back in. My guess is that you've got bad fuel. Dump the fuel, clean the tank or buy a new one and start fresh. Change the primer bulb while your at it.

Oh, a word of caution about your water pump. A bad impeller doesn't always look bad like you see in some of the pictures. Once you remove the pump cover you loose the original set. Re-using the old impeller is not something I would advise.

 

[Mike(nj)]

Re: Water/wet spark plugs HELP ASAP!!!

OK, went down the the Mercury dealer and got a new thermostat. I'm taking both tanks with me too.........one is completely clean with new reg. gas mixed to 50:1 & the other is the mix given to me. Wish me luck! I can't wait! I think this motor is going to fly compaired to the 9.9.