Water on spark plugs...

[ROCKMONSTER]

Hello I am new to the forums, new to boating in general, i have a 1977 Evinrude 75 serial num 75743s . Engine runs great on muffs or on start up at lake, boat will come to wot, n plane out nice for min or 2 then sputters n loses power, If i idle down seems come out of it some but wont run same after, Had a mechanic friend come over n clean all 3 carbs, all were nice adjusted all 3 floats as they were all not flat as should be.. Moved on to check compression, top cyl -150 mid cyl-140
bottom cyl -150, on checking compression he noticed water on plugs n said well there is problem, bad head gasket.. Looking for any other input as to what could be causing the issue, any input n suggestions greatly appreciated..
Rocky

 

[F_R]

Happens way too often. At even the slightest hint of overheating, the exhaust cover baffle plate warps which makes the gasket leak and squirt water into the exhaust ports. It will totally destroy the powerhead if not tended to. New gaskets alone will not fix it, you have to deal with that warped plate.

EDIT: Picture here:
http://s19.postimg.org/pjck39c37/3_CYLINDER_EXHAUST_PLATE.jpg

 

[jrs_diesel]

Your compression seems really good, but normally you will have bad compression on at least one cylinder that would indicate a water leak into the combustion chamber. EDIT: F_R mentioned the exhaust plate as a source of water on the plugs. I would look into the cooling system too.

Your problem tells me you have a fuel delivery issue. Either your fuel pump cannot keep up, or your fuel tank is not venting correctly. What happens if the fuel tank is not venting is as the engine suck fuel the tank, air has to replace what the engine takes out. If the tank vent is clogged, air cannot get in and this creates a vacuum in the tank. Eventually there is enough vacuum suction in the tank that the fuel pump can't pull any more fuel for the engine, and the engine becomes starved for fuel. The primer bulb is sometimes sucked flat too.

I don't know if you are using portable tanks or if your tank is installed in the boat. If using a portable tank, make sure the vent is opened up. Usually is a little knob on the gas cap. If it's a permanent tank, you can loosen the cap so the tank can breathe. Also, you can use a portable tank and hose to eliminate the boat fuel system entirely. If performance is the same on the portable tank in this case, I would suspect that the fuel pump can't keep up with the engine demand.

 

[ROCKMONSTER]

Tank is portable n is self venting no lil breather screw, n it gets fuel fine, after the water gets in is when it goes to pot, cause water don't burn to well.. I have ordered a head gasket, and a exhaust man gasket, ill have to see if anything is warped.. Any more suggestions? Thanks for the suggestions so far guys i appreciate it..

 

[ROCKMONSTER]

Tank is portable n is self venting no lil breather screw, n it gets fuel fine, after the water gets in is when it goes to pot, cause water don't burn to well.. I have ordered a head gasket, and a exhaust man gasket, ill have to see if anything is warped.. Any more suggestions? Thanks for the suggestions so far guys i appreciate it..

 

[F_R]

When you get that exhaust cover off, you will see why it warps. Right around the exhaust ports, there is a gasket on one side of the plate, but it is not supported by anything on the other side. Too bad such a fine engine is compromised by such a fault.

 

[ROCKMONSTER]

Ok ill def keep in mind, my boat mechanic friend said in his exp it is 90% of time head gasket n that is why my middle cylinder is 10 pounds off from others, he seems to think the break is in middle cylinder gasket.. All greek to me, we shall see . When motor runs it runs well, n it takes lil while to get in, i noticed when i turned key no beep so we r going to look into the over heating alarm..