Leaking petcock

[tom203]

My petcock has no shut off.

Yes, it does or at least it did when it was working correctly
the vacuum petcock automatically shuts off when there is no engine vacuum - it's like magic!

[Admiral Beez]

From you description, you need a new mechanic.
Petcocks don't wear out, the rubber bits go bad, or the vacuum diaphragm goes bad.

You probably spent the better part of the cost of a new petcock having someone badly rebuild yours
Time for a new one.

You might be right. As best I can tell, the fuel is leaking from above the petcock, where it matches with the tank underside. I’ll be asking the mech who did the original work to recheck everything on Tuesday before install the NOS replacement petcock.

[bwringer]

You might be right. As best I can tell, the fuel is leaking from above the petcock, where it matches with the tank underside. I’ll be asking the mech who did the original work to recheck everything on Tuesday before install the NOS replacement petcock.

it sounds like the surface was dirty or messed up somehow, the o-ring wasn't correct or was damaged, and/or the sealing washers weren't replaced on the mounting bolts.

[Admiral Beez]

it sounds like the surface was dirty or messed up somehow, the o-ring wasn't correct or was damaged, and/or the sealing washers weren't replaced on the mounting bolts.

The NOS petcock is now installed and totally dry. Total cost new petcock installed $160. I have the old petcock and may take it apart for my own learning.

This winter I'll be taking off the tank entirely as I'm shipping out the sending unit for a rebuild.