bendix carb question

You know what? We tried lapping it in with valve grinding compound,
with toothpaste, and jeweler's rouge (not in that order), and it didn't
work. But the whack with the hammer stopped it from dripping.

Admittedly I don't know a whole lot about carburetors, and even less about
airplanes, but that doesn't make very much since to me. I'm not saying your
wrong, just that I'm having trouble understanding.

On 24 Jun 2005 19:21:43 -0700, wrote:



LCT Paintball wrote:
The last Stromberg NAS3A1 I rebuilt we tested on the bench and the
steel needle would not seat completely. It dripped a little, so the
A&P/IA who signed it off whacked the needle against the seat with a
hammer. Which stopped the leak. Don't ask me how hard to hit it.
It must be done gingerly, deftly, prayerfully.


Wouldn't it be safer to lap it in with some very fine lapping compound?

You know what? We tried lapping it in with valve grinding compound,
with toothpaste, and jeweler's rouge (not in that order), and it didn't
work. But the whack with the hammer stopped it from dripping.

One of our gurus with A-65's in Alliance, OH also uses a hammer to
"seat" a steel needle.

Was a VERY common method of stopping drippy carbs on everything from
Model "A"s and '35 Chevies to farm tractors in the sixties/seventies.
When doing a carb rebuild you would check the needle tip for wear ( a
standard "zip kit" did not include needle and seat - only gaskets,
diaphragms and rubber parts), and if there were no "rings" worn in it,
a sharp tap with a small tack hammer virtually guaranteed it would not
leak when assembled.Lapping put "rings" in the tip, virtually
guaranteeing the needle would stick (closed)at a most inoportune time.