Is it necessary to replace the base gasket on a 1957 7.5 evinrude after removing powerhead if original gasket still looks okay ? I will be replacing the impeller and also I want to make sure all the parts are installed correctly just under the powerhead and replace whatever needs to be replaced.
I’ve reused the base gasket many times. As long as it’s not broken or torn up, you can coat it with some Permatex #2 sealer and go with it.
I would replace the cork seal on the upper end of the driveshaft, as well as make sure the correct spring and cup washers are present. Very important on that motor.
Not replacing the gasket is a gamble, might leak afterwards even with sealer….But, a leaky gasket won’t cause any harm, just having to pop the powerhead again and replace it….
Like Jerry says, don’t overlook the lower seal components though….I would definitely replace the cork gasket and carbon seal oring. These parts are not worth the gamble and will cause harm if the seal assembly is not working properly….
I have reused almost as many base gaskets as I have replaced. I agree with Don that it’s a gamble and I have had them leak and had to replace them before. Most times they don’t leak. I always clean the mounting surface it didn’t stick to thoroughly before replacing the gasket. I usually use grease between the gasket and the sealing surface. I have not had any trouble with grease and it makes pulling the powerhead back off no problem.
Definitely always replace the cork gasket and the carbon seal O-ring when pulling the powerhead off a motor you don’t know the history of.
-Ben
Is the base gasket expensive or no longer available?
You would be right at the point of installation.
Might be worth replacing it just for piece of mind.
If it is available and not cost prohibitive.
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