Sending Unit Gasket Leak
 

When I fill my gas tank to the top, gas leaks out through the sending unit gasket.
It is was installed without gasket cement, using the rubber gasket supplied only.
Stainless screws are self tappers directly into plastic tank, original threads are shot.
I know the easy answer is to not fill the tank, but I want to prevent water from leaking in also.
Suggestions? (see picture)

My sons boat is having the same issue , Can't you just get another gasket or make sure all the screws are tight, I don't think I would use any type of caulking but the heavy hitters will give you the right answer .

My old tank had the same issue, but i was an aluminum one. I used some evinrude gasket sealer i had

Worked great

Get a new gasket and a petroleum resistant sealant, I use permatex ultra black on anything that comes in contact with oils or fuels

if threads are gone you are in a losing battle. You might have luck with threaded inserts aka T nuts or burled nuts.

Maybe consider a new tank. Looks like you got your moneys worth out of that one.

Gas in bilge is nothing to fool with.
Water in gas is nothing to fool with.

Is it a plastic tank or aluminum

Plastic tank

JB Plastic weld in the holes
take the sending unit out, put some duct tape on the bottom of the holes and JB it
I'd go up a screw size and drill out the holes in the sending unit one size up too


Option B New Tank

The original nuts/threaded inserts are brass and molded into the tank. The original inserts will probably be covered in corrosion. Spray them with penetrating oil and use a dental type pick to clean them out. they are about 1/2 in deep. when you can see them clearly, run a flat bottom tap through each one Carefully, Slowly. backing it out often to clear the crud. dont push it too far. spray frequently while doing this. IF the inserts are damaged you may have to go slightly larger. get stainless screws to replace the lost originals.
it worked out fine and i put it back together a new gasket and without any sealant. sealant is not recommended on these rubber gaskets.
hey anybody here know the size of these brass inserts and the original screws?