Water in #1cyl. 1985 60 hp mariner

Hello Guys,

I desperately need advice on a 1985 Mariner 60 3 cyl. I'm having a problem with water intering #1 - top cyl. I have replaced water jacket cover gaskets twice, one time with gaskets only and second with high temp silicone added to them -both sides. Semms to run fine for a minute or two then water fouls only #1 cyl. again. Motor has 130 compresssion on the cyl. in question and block and plates have no visible sign of damage or warping. Any ideas on where else this water could be coming from?

Thanks for any advise!!!

Andre' Wells Hou. TX

Re: Water in #1cyl. 1985 60 hp mariner

most likly a pin hole in the block casting.

Re: Water in #1cyl. 1985 60 hp mariner

I was afraid it was something serious. Is it repairable, or should I be looking for new block? Also can I run any type of radiator type stop leak product through it with any luck? The problem is, the motor is real clean and I have replaced all electronics and many other items. I don't know whether to cut my losses now and be left with a good parts motor or continue?

Thanks for your help and quick response!

Re: Water in #1cyl. 1985 60 hp mariner

Silicone on a gasket does NOT ensure a perfect seal, especially if the surfaces are not near perfect and the silicone is still wet, it often acts like a lubricant, causing the gasket to slide out of position sort of like squeezing a tiddly-wink.

Before I condemn the block I would re-inspect the exhaust side VERY carefully.

Verify gasket compression.

Ink every sealing surface with a large felt marker then carefully slide a fine flat file along every surface and inspect your 'witness' marks. Any ink remaining should prove irregularity in the seal that could be your culprit.

I use silicone products, but I spread it so thin it is almost not even there, and I let it dry to tack-free before assembly to prevent any 'sliding' of the gasket. Any thicker application I assemble and tighten bolts to only 'finger' tight until the silicone is fully cured, only then is it safe to 'torque' bolts to spec.

Re: Water in #1cyl. 1985 60 hp mariner

Rod Bolt & Charlie B,

Thanks for your advise. I will try a more meticulous approach with new gaskets after checking sealing surfaces with straight edge. I will post my results.

We all should be very thankful for free - experienced advice available on this forum!!!