fuel tap thread size

[outboard]

Hi guys, I'm working on an old (was seized) 40+. It had a glass filter fuel tap on the tank so I decided to change that to a brass fuel tap, however, the thread size on the brass tap is much smaller and won't fit the tank. Can anyone tell me what thread size differences there are in these fuel taps so that I can try and get an adaptor to get the brass tap up to the fuel tank size. Are all fuel tanks threaded to one size? I bought this brass tap on the bay and might have been duped (maybe not) but it has happened before, would you believe that?

Gerry

[charlesp]

All the fuel tanks were threaded to one size, but for the life of me I can't remember what size that was. Best bet is to wait for the other Charles, he may know off the top of his head.

[Charles uk]

He might, but he doesn't remember, I think it's a cycle thread.
All cycle threads are 32 Tpi, but can't find a loose one to measure.

[Horsley-Anarak]

The thread size that takes the Ewarts fuel tap is 1/8" B.S.P.

This is a 28 tpi thread with a major external diameter of 0.383".


H-A

[Rex NZ]

Concur with H-A

1/8" BSP

Don't confuse with 1/8" NPT American. These look the same

Rex

[outboard]

Thanks for the info guys. I would reckon either my tank has been tapped out, or, which is more likely, I've been sold a useless brass fuel tap.
Will check it against one in my other 40+ and let you know.

Gerry