Mercury 50 HP 1964 - cutting a cylinder block cover gasket

[w2much]

On this motor after I installed a water pump the cylinder block cover gasket started to leak in several areas. I removed the cylinder block cover and was able to save the old gasket for a pattern possibly. The cyl block cover has some pitting from age but certainly still has integrity to reuse. The old gasket came off pretty clean. There was some sealant but it came right up.The gasket seemed to be a thin gasket paper. Perhaps home cut. I went out and purchased a thick .038 gasket paper to cut my new gasket and install with some aviation gasket sealer. I thought it was a great way to go but am now having second thought. The gasket paper purchased at local NAPA seems like a type of virgin craft . Says good for oil fuel and coolant. I was wondering if it would hold up or deteriorate due to the nature of the flowing cooling water. I like it because it is thick and with sealant will certainly hold up between any two surfaces. It is just the nature of all of the flowing water from the water pump. Just wanted your thoughts on this. Thanks

 

[jimmbo]

The water jacket cover tends to warp if the engine gets even slightly hot. Often it will leak again when the gasket is replaced, not immediately but give it some time.
Check with a Mercury dealer to see if the original gasket is still available, the part number may have been superceded/updated several times, of if an aftermarket is a choice. A hardening flexible sealant(not Silicone) can be utilized to help

 

[w2much]

The water jacket cover tends to warp if the engine gets even slightly hot. Often it will leak again when the gasket is replaced, not immediately but give it some time.
Check with a Mercury dealer to see if the original gasket is still available, the part number may have been superceded/updated several times, of if an aftermarket is a choice. A hardening flexible sealant(not Silicone) can be utilized to help

Yes sir, that is my concern.
I have found the gasket available for about 25 bucks. The money is not the issue. I was just thinking that if the cover was slightly warped ( does not appear to be) that a thicker gasket would be both curative and preventative. "Not silicone" good reminder thank you. My real question though . Is a good gasket paper acceptable to use in this situation or might the flowing water tear it down. If looking at the gasket it has holes cut for flow and of course the 4 holes for the spark plugs. I appreciate your reply.

 

[jimmbo]

I have no idea why there would be holes for flow, there is no need to cool a jacket cover, Maybe mercury was punching holes and using the plugs for smaller gaskets. When I mine was leaking 32 yrs ago, I was going to double up the gasket material at the spark plug hole area, but Mercury provided me with a new cover, no charge and with one gasket, installed with no sealer, it never leaked again the remaining 11 yrs I owned it

 

[merc850]

If you are planning to clean the cover don't sand the areas around the spark plugs they are slightly raised to seal the gasket.

 

[w2much]

Understood. I cut it and installed it, no leaks. What a bear getting the bottom left nut and bolt in place and tight. Thanks for your replies. Now please check my other post. Same engine 1964 50 Hp Mercury, Spark on 2 cylinders.