fuel sending unit leking

[bigeasy1]

I meant "Leaking", not leking

Who's the rocket scientest that decided to use sheet metal screws instead of machine screws to hold down the face plate of a sending unit on a gasoline fuel tank.?
My last sending unit failed so I replaced it with a new Wemu unit that works great.However,when I fill the tank to capacity(55 gals),gasoline leaks out of one of the sheet metal screws used to hold down the plate.It doesn't leak around the gasket,it leaks past the threads on the screw.
It's not a huge amount,but its enough to smell up the boat,and definitely not safe.This only happens when I fill the tank to capacity.
The leaking stops once a few gallons are used.
With only a 55 gallon capacity,its important to have as much fuel as necessary to make needed trips to fishing areas.
I have tried everything to stop the leak but most sealers don't work.
Why wouldnt the builder use studs instead of screws?with all sending units being mostly standard, studs would seem to make sense.,that way you could tighten it down with nuts.
Anyone have any ideas or know of a sealer to remedy this problem?

[Bushwacker]

Suggest you drill & tap for next bigger size machine screws and use Permatex No. 2 gasket sealer. It's one of the few sealers I know of that's impervious to gasoline.

[Normagain]

The Permatex Aviation Form-A-Gasket is also good for gasoline as a thread sealant.

http://www.permatex.com/resources/faqs

[pelican]

no "builder" did that...those screws should be 10/32 stainless...the tank in the area of the sending unit should be "doubled".

common "backyard" repair "attempt" is to use self tapping screws,when there's a problem with the fasteners for the sending units...

easiest cure is to use a pneumatic drill,drill new holes and tap them -situation solved.

DO NOT use an electric drill or a battery powered drill - these "spark" ! sparks and gasoline do not play well together


stern drive powered boat ?? fuel leak ?? recipe for disaster !

wema senders are definatley the best available


aviation form gasket - a good sealant to use,when the tank's surface is slightly compromised in the gasket surface area - brush it on...works well on the screws holding the sender down too