[Christ]

Originally Posted by gjgerhard

Yes, that's right, it's a fairly conventional carburetor. I thought about setting it so that the butterflies close completely, but there are at least two possible downsides to that approach that I can think of: one, shutting the carb completely will result in vacuum levels never intended...that would probably work the valve seals harder, among other things, and two, I believe that at least some carbs have a "dribble" port below the butterfly...the increased vacuum would suck that one harder, maybe even making the problem worse.

As you point out, letting it get down to idle is one way to avoid this problem. The other is shutting off the fuel. That is how diesels are stopped normally, and I remember that my Piper (Lycoming) had a fuel shut-off as well (Marvel updraft carb).

Sure, you can shut off the fuel, as long as you do it with an electronic solenoid that closes the main jet in the bowl. (Manual works, too). Otherwise, your engine will keep running until the bowl is empty, which isn't good, either.