86 sea ray 5.7 l running rough, water on spark plug

the newfoundler

Recruit
Joined
Sep 3, 2009
Messages
5
Hi guys, I am still having trouble with my boat. As I said in an earlier post, it all started last fall with a failing fuel pump. The pump ruptured and dumped a lot of fuel in the base. Changed the oil and filter, but ran rough ever since and a lot of fumes coming out of the valve covers. I changed the oil twice yesterday, to make sure it was completely rinced and took it for a little run last night. Still the same, maybe less fumes, but still smoking and running rough under load. I made it back to my mooring last night and the engine would not idle at all. It ran as if it was running on 7 cylinders only. I went down today and the engine won't start at all. I pulled out the plugs and noticed that they were all a little black, not fouled, but dry and sooty, ( normal)except for # 3 cylinder. That spark plug was shiny like a brand new plug and seemed to be water bubbles on it.Any ideas as to where I should go next? I double checked firing order...1-8-4-3-6-5-7-2, all correct. So far this year I have put new plugs, wires, cap, rotor button, ignition sensor in distributor. I also put on 2 new risers. The boat was not overheating, but I decided to take off risers and manifolds last fall to check them when i winterized it and noticed that the risers were starting to get plugged,, so I replaced them anyway. I checked the compression last fall and all had around 140 psi except # 8, which had 129. Anyway, the boat will not start now and I am frustrated. Would it be a head gasket or manifold leaking water into the cylinder? I have not investigated it any further yet as I have been sick, not feeling up to it and looking for some direction. Any input on my dilemma would be greatly appreciated.
Thank you
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,581
Re: 86 sea ray 5.7 l running rough, water on spark plug

I will assume you replaced the fuel pump
Firing order listed above is correct
Check for 12V at the coil with the key in run position
Determine if you have good spark going to distributer
Is fuel making it to the carb
If you have spark and fuel the next would be compression test
 
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