problem sealing fuel sender mechanism in fuel tank

[Captainfoss]

When I bought this boat a month ago, the fuel gauge didn't work. the guy I bought it from said he checked the gauge and that was working, but it was the sensor (the sender) in the tank that was caught in the down position.
I removed the 5 bolts, pulled the unit out and fiddled with it until it moved freely.
When I placed it back into the tank, with the gasket, I couldn't get the bolts to thread in all the holes. I rotated it 90 degrees and was able to place the bolts back into the holes and tightened them. I thought I had tightened them all sufficiently to make the seal. I filled it with fuel this morning and subsequently found that I had overfilled it and gas was leaking through the seal and into the bilge. I tried tightening the bolts and found that one appears to be stripped. Four of the bolts are one size and one is larger. It would appear that I need to re-thread the bolt holes into the tank. Is there any other way I could reachieve the seal on this unit without emptying the tank, removing all the vapors, are drilling in new threads?
Please let me know if you have any suggestions regarding this problem. Thanks in advance for your help with this.

Bob Foss
Vista, CA.

[mmwjr]

Since you reused the old gasket you should have used a sealer such as Mercruiser perfect seal. I don’t know of any good fixes that don’t require retapping new threads.

[jparsons121]

Agreed. I had one stripped hole in mine and just ran a tap thru for one size up. Be sure to coat the tap liberally with grease to capture the chips. The hole pattern is offset so it also helps to mark the plate and the tank with witness marks so it goes back in the same orientation.

[Captainfoss]

Thank you so much. I ended up buying a new sender unit and got it installed successfully. Thank you fir everybody's help.
Bob

[Captainfoss]

Thanks!