M carb problem

Anonymous-0

Well-known Member
working on a m carb on a m tractor and with tractor running it would only run w/ choke on. Gas was also pouring out of the hole in the bottom. Pulled bowl off and found that there is supposed to be a plug of some sort in the bottom with a looks like a freeze plug drive in cap over it. I rebuilt one along time ago. Is it like a lead plug thing?? Not sure what you call it. Well anyway i need to figure out hoe to fix it. Cause its pulling air through this thing( hole about 3/8'' diameter) Does it come in a rebuild kit?
 
That is a drain in case you over-choke the engine or the needle & seat are not shutting off the fuel flow. It has no effect on carb adjustment.
FARMALL H & M CARBURETOR & GOVERNOR ADJUSTMENTS

Note: #1, 2, & 3 adjustments are done with the engine not running when the carburetor has been removed & replaced.
1. Loosen the 2 screws that are holding the governor tube to the governor housing. The clamp is slotted to allow adjustment. Tighten the tube-to-carb screws; gently tap the tube so it "centers" itself, & then tighten the tube-to-governor screws.
2. Remove the top cover on the governor housing (has the pipe going to the cylinder head) and check governor to carburetor synchronization. Remove the cotter pin so the clevis pin can be removed. With the operator's throttle lever set wide open and rotating the horizontal rod upward to wide open throttle position, the clevis pin should just slip into the rod that is in the tube. This horizontal rod should rotate freely allowing the carburetor throttle plate to move from idle to wide open. Adjust the clevis height if needed & lock the nut. You may need small fingers & right-angle needle nose pliers to make the job easier. Return throttle lever to idle. Re-attach the top cover.
3. Carb adjustment: idle air screw is set at 1½ turn out to start with; high speed mixture screw is 2½ or 3 turns out.
4. With the engine warm & running at wide open throttle (WOT), turn high speed mixture screw (on the bottom facing down to the rear) in until the engine begins to starve for fuel. Then turn the screw out until the engine begins to blubber. Now find the "sweet spot" in between the two settings. If you are working the engine (plowing, etc.), then the high speed screw needs to be turned out ½ turn or more beyond the "sweet spot" to be sure the engine isn't starving for fuel and can develop its rated power.
5. The same procedure can be followed for idle mixture with the addition of setting the idle stop screw (just to the rear of the governor shaft tube) to adjust the low speed RPM.
On the "H"& “M” carb, the idle mixture screw (faces to the front just below the idle stop screw) is an air adjusting screw so turning in will richen the mixture and out will lean the mixture.
Repeat the carburetor adjustment procedure again to make sure “all is well”.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top