Fuel tank gasket

[NYSail]

Hello all,
I have a plastic fuel tank in my beneteau. I had removed the sender and when I replaced could not get a good seal…. Problem with the plastic is that you really can’t tighten the screws down as they will strip. The sender has a black tar like gasket material…… any ideas what this is or recommendations? It leaked after I did this (2 seasons ago) and I sealed the sender with an epoxy type sealant however want to remove and replace the sender as it no longer is working and would love to have a non leaking tank with the ability to get into tank of need be.
Thanks
Greg

 

[Ralph Johnstone]

The black tar like material is Permatex #2. Nothing else will stick to poly.

 

[NYSail]

Thanks!

 

[Sailor Sue]

I had a similar situation, but with an aluminum tank. The tank had 3 large inspection ports, the covers being held in place with machine screws into the tank. Several of the threaded holes had stripped out, making it impossible to get a tight seal on the covers. I ended up drilling and tapping the tank for the next larger machine screw. Then I screwed machine screws into the tank FROM THE INSIDE with epoxy between the screw head and the inside of the tank. Permanent lock-tite might have also worked. I then made gaskets, I think out of sheet nitrile. The covers were held in place with nuts so I could really tighten them in place.

The original covers also had the same black goop that you mentioned. When the covers were installed some of that goop oozed out into the tank. At least one piece of cured sealant broke off and eventually got sucked up into the fuel line. The diesel had a vacuum gauge and I could never figure out why the vacuum was so high, even after cleaning the tank and starting with new filters. The plug of sealant eventually worked it's way up to the elbow at the top of fuel pick up tube where it totally shut off the fuel supply, but not before I had replaced all the fuel lines in an attempt to solve the fuel issue.