I have a 1996 mercury 150 EFI i changed waterpump n checked thermostat yesterday now i have a leak around thermostat housing there is no gasket there and from what i read there is not suppose to be one. would it be ok to put a little permatex gasket sealer  on it . I have took it off twice cleaned and put back on and it still leaks, Thanks

OK just got back from the boat place the gasket on these is the rubber seal that goes around the thermostat you have to get them separate. they look like just part of the thermostat. said a lot of the 90 model motors are like this and maybe more they didnt say, so for future reference five years from now when i cant remember i can do a search on here and find this lol.

Congratulations on solving your problem without the help of Bassresource.com.

Best of luck with your memory problem too..