50 HP Mariner-Water Leak at Powerhead!!

[Skiffhunter]

OK,
My 1985 50 hp 4cyl Mariner was running fine then I noticed intermittent hesitation and loss of power. The 4th plug wire had some rust around it and was obviously getting wet. I pulled the plug and it was very clean. The others had oil burn residue.

The other day I noticed water leaking out of the side of the powerhead (cylinder block) cover and out of a broken (I never noticed this till then) bolt hole near this #4 cylinder. Not good. As the engine hesitated, I could hear the *tick* of the spark in the wires.

I will do a compression test today. However, is this a matter of replacing the head gasket, the water jacket, the exhaust gasket, or all of the above? SHould I assume its gonna need a total rebuild or should I try to replace those gaskets first, assuming compression comes out ok.

The sun finally comes out in San Diego and now this...PLEASE HELP!
Thanks.

 

[Dave1027]

Re: 50 HP Mariner-Water Leak at Powerhead!!

Go slow. Don't assume the damage to be so great. I think the first thing is to replace the broken bolt and do the compression test. Maybe it's just the wires getting wet and arcing.

 

[westexasrepublic]

Re: 50 HP Mariner-Water Leak at Powerhead!!

sounds like you just have a water jacket gasket leak. your loss of power is something else. do a compression test and check your electrical, those wires probably have MERC ROT. typical shetty wiring that rots and arcs. that in turn burns up your rectifier and switchbox....stuff like that.

 

[Skiffhunter]

Re: 50 HP Mariner-Water Leak at Powerhead!!

Do you think this may be just a water jacket problem even with the spark plug looking like it was "steam cleaned"? Also, as stated, the motor runs poorly and it seems like it may be running on three cylinders?

Thanks for the reply guys. Keep em coming!