Water on plugs. here, then gone???

[Floater49]

Motor:1974 1150 Inline
Time since rebuild: 15 hours (estimate)
Plugsermagap
Compression (1-6):119-120-120-122-120-120
My issue is that yesterday I found out that it was not charging (seperate Issue)when the battery pooped out in the middle of the lake when I tried to start up and move. As it was cranking, I feared that I had flooded the engine, so I pulled plugs to clean it out a bit. When I pulled #2, I saw some light brownish stuff on the plug. It had some water bubbles on it. Not many, but a few small ones, and it looked foamy. So I pulled more plugs and they looked fine. Long story short, I got home and looked into it a bit further. I started with a compression check, thinking if there was a bad gasket, I would have low numbers. Obviously not. Pretty consistent. I then refired the engine and let it run a bit on muffs at warm up RPM. I shut it off and looked again. Now I had the foam on 2 and 3. I switched plug positions and refired. Now I had it on 1, 5 and 2. So I got a fresh can of fuel and ran it from there. Same thing, but different plugs.
The reason for rebuild by the previous owner was an over heated "2 Cylinder and scored cylinder. Pistons are now .015 over I think.
I am wondering if I have a bad batch of gas, or what else could it be? Can someone help?

 

[corm]

Re: Water on plugs. here, then gone???

Hi,

Well you have a few possibilities.
1) They did not high temp silicon the exhaust plate when they put it back together. Early engines had a bead run along the exh divider plate. Exh pulses can suck or blow water around.
2) If it is real humid you can see water on your plugs most any time.
3) running it on a hose keeps the engine much cooler than in the water causing condensation on the plugs. (depending on where you live of course some lake water is colder than well water)
4) If you have a water cooled exhaust port plate the gasket could be leaking.
It is normally replaced on a rebuild. (I am not sure a 1974 115 had this plate and have no way of checking now)

The engine runs poor with water intrusion. I had written an adventurous way
to do this but had second thoughts about safety. So what I would do is run the boat on the trailer at the landing about 2500 to 3000 RPM for 30 seconds or so and turn off the key. Then check your plugs and see what they say.
You will not need to back it in very deep. Say just cover the cavitation plate. Also make sure it is ok to run a boat on a trailer. Some places do not let you drive a boat onto a trailer so you can't run on the trailer either.