Thermostat Gasket Sealer?

[tmasloske]

I recently replaced the thermostat on my '68 Evinrude 18 HP. I used OMC gasket sealing compound and a new gasket. When running the motor, I noticed some water seeping from the thermostat gasket area. Did I not tighten the bolts enough? Or, should I have used scotchgrip adhesive/gasket instead?

Thanks in advance!

 

[ezeke]

Re: Thermostat Gasket Sealer?

The screws may be bottoming on debris in the holes. Chase the holes and blow them out so that the screws can seat properly. With a new gasket the water should not leak even without a sealer. There is not enough water pressure to require much torque.

 

[Benny1963]

Re: Thermostat Gasket Sealer?

also check your thermo cover for flatness with strait edge may be warped
i had one on rebuild from overheat that would not seal

 

[tmasloske]

Re: Thermostat Gasket Sealer?

Thanks for the tips. I replaced the cylinder head with a used one because the previous ower had helicoiled the lower spark plug threads and it "spun out" on the spark plug. I installed a new thermostat and gasket in the process. The motor ran great with the "new" cylinder head. The only issue was the water leaking from the thermostat gasket and pooling up next to the housing.

I was able to tighten the bolts more. But, I have not run the motor again. I'm hoping this stops the leak. I may have just been afraid of over-tightening the bolts. Oh, and I did torque the cylinder head bolts to spec. I plan on going fishing this weekend if the wind lays down.

 

[samo_ott]

Re: Thermostat Gasket Sealer?

The screws may be bottoming on debris in the holes. Chase the holes and blow them out so that the screws can seat properly. With a new gasket the water should not leak even without a sealer. There is not enough water pressure to require much torque.

I have a '66 18 and also changed mine and did not use sealer. I agree with the above. It should be fine.