Fiberglass diesel tank sealant

[Stirfryd]

Hi all,

I never completely filled my integral fuel tank after a repair that involved cleaning the tank by removing the site gauge (located on top of the tank) and working thru the roughly 4 inch diameter hole. The guy that cleaned it out cut a black rubber gasket, screwed the site gauge/coverplate back down and called it done. I filled my tank and discovered that this is not a tight fit. Diesel on top of the tank. So like most jobs on boats, its better handled by me the owner who will do it properly. My only question is what materials I should use to seal the cover plate with. Rubber gasket material and a compatable sealant of some kind that diesel will not affect? The top of the tank is not a smooth fiberglass surface nor very true. Its also painted with bilge coat. Suggestions?

[model 10]

Well you have to get rid of the bilge cote first then you need some 2 part Poly Sulfide sealant. Wax the gasket on the sender side (so you can get apart again sometime) and glue it together.