A Leaky Fuel Shutoff Valve

Here's a leaky fuel shutoff valve from a snowblower engine.

And here it is minus that tubing remnant. (The barbed nipples are sized for 1/4" I.D. tubing.)

The valve's stem packing is shrunken/worn-out, so the valve leaks even when it's closed. The valve's knob is swaged onto the valve stem, so the valve is not meant to be repairable. Still and all, I'd like to get a look at the failed stem packing, so I'll drill away the knob's swaging. That should let me get the knob and the packing nut off.

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Valve Dismantled

So far, so good.

The packing washer is an embrittled ruin. The stem's diameter is just shy of 3/16". I've drilled the stem with a No.43 drill, and tapped it 4-40 so I can reattach the knob with a short screw. I'll see if I can persuade a 5/32" x 9/32" O-ring to serve as packing.

Here's the whole array with the red paint stripped off, and the stem burnished.

At the very left side of the photo is the 4-40 x 3/16" screw that I mean to reattach the knob with. I'll put that all together with WD-40 as an assembly lubricant, and blue threadlocker on the knob retention screw.

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And here we are.

The O-ring appears to have seated into its recess in the packing nut. The knob is back on securely and the valve's 'feel' is ok. I just may have a serviceable fuel shutoff valve here.

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