[SantaFe66]

I'm pretty sure that the fitting that screws into the manifold is 3/8" pipe, same as yours. However, the top part of the fitting that the nut on the sender fits on is probably not long enough so the nut doesn't bottom. The sender still moves when I screw the nut on as tight as I dare.

I'll take a pic and see if I can make this clearer.

It's really a stupid problem and it's preventing me from starting up the motor since I'm sure it will leak big time.

Thanks for your reply. I'll post a pic tomorrow.

Paul