M carburetor project...

Must be the week for "M's" around here!

Fellow bought a tractor with the carb just "expertly overhauled", but it wouldn't idle and ran terribly.

The "carb expert" left the throttle plate screws almost loose, and had the throttle plate so cocked on place there was a LARGE gap at the idle mixture port side when the plate touched at the opposite side.

The float pivot pin was out of the hanger on one side, as the hanger was bent on the slit side that grips the pin so the float was hanging like the wing on a wounded duck.

Apparently, an air bleed jet (nozzle) is missing altogether. I'm now trying to track one down.

<img src = "http://i167.photobucket.com/albums/u125/27Grainfield/N%20Ford/IHcarb1.jpg">
Gap at throttle plate before adjustments

<img src = "http://i167.photobucket.com/albums/u125/27Grainfield/N%20Ford/IHcarb2.jpg">
Gap at throttle plate before adjustments, photo2.

<img src = "http://i167.photobucket.com/albums/u125/27Grainfield/N%20Ford/IHcarb3.jpg">
Gap at throttle plate AFTER adjustments.

<img src = "http://i167.photobucket.com/albums/u125/27Grainfield/N%20Ford/IHcarb4.jpg">
Apparent missing jet. (Or, lack thereof!)

Yep, it's missing the idle metering jet, except it looks to be broken off in the picture. Maybe not? Common problem on the M carbs due to not knowing how to take one apart.

Call your local dealer; you can get gas or distillate jets.

49798D72 JET IDLE METERING JET

49798D75 JET IDLE METERING JET (For "Fire crater increased power package")

Go to bottom right of page: click "begin your search", enter "Farmall M"
On Line parts

what is the main jet setting on an M?

Did you see the price... about $25.00 for a little brass jet!