Farmall MD (Won't Run On Gas Side)

Eddie V

Member
Hello Everyone,

I have a MD Farmall that will not run on the gas side. The magneto is rebuilt and I cleaned the carburetor
I still cannot get it to run on the gas side. It smokes a little out of the exhuast when turning over but
will not fire or spit. I guess I will pull the carburetor and look over things again. Any advice?
 
I assume you are getting spark. If it has a mag cutout make sure that switch is not stuck. The carburetors are pretty simple and do need to be cleaned once in a while.
 
How much choke are you giving it? Mine was happy with full choke for several turns, then bump it in a little as it stays running. I would make sure it is getting spark, then fuel. Jim
 
One thing you need to check is whether the flapper in the gas manifold is opening when you switch it to gas. One year my 650-D would not start/run on the gas side. Found that the spring that has to open the flapper in the manifold was stuck in the diesel position. After manually getting the unit to flip open and then spraying it with penetrating oil, it started right up on the gas side. Now every spring when I start it for the 1st time, I check that it is in the correct position. Something to check. Al
 
I can't remember off hand what my MD carb linkages look like, but I believe they were basically the same as the UD554 my grader had in it. Part of the switch over mechanism had a linkage/device that would seat the needle and prevent gas from flowing into the carb while in diesel mode. Sometimes it would stick after being in diesel mode and then wouldn't allow gas into the "bowl". Something to look into maybe. As stated, I THINK MD carbs do the same thing, but not certain going off my memory.

Ross
 
Just because the mag was rebuilt does not say it is working as it should. Trouble shoot then parts always .
#1 make sure you have a good blue/white spark that will jump a 1/4 inch gap at ALL 4 plug wires.
Next check that you have a good flow of gas out of the carb drain plug. Should fill a pint jar in about 3 minutes.
 
(quoted from post at 18:41:09 09/01/15) I can't remember off hand what my MD carb linkages look like, but I believe they were basically the same as the UD554 my grader had in it. Part of the switch over mechanism had a linkage/device that would seat the needle and prevent gas from flowing into the carb while in diesel mode. Sometimes it would stick after being in diesel mode and then wouldn't allow gas into the "bowl". Something to look into maybe. As stated, I THINK MD carbs do the same thing, but not certain going off my memory.

Ross

You are correct.
 
MD's have the same mechanism to seat the needle valve in diesel mode. That's why cleaning the carburetor is a good idea.
 
You did have your magneto rebuilt? Or got a replacement? Diesel magnetos turn backward to gasoline so they are not interchangeable.
 
I can't remember if that has the little section that can be a half turn off, and still look right like the H or not. If so it might be half off.
 
Yes, I think what you are saying is that you can install the mag 1/2 turn off. Yes you can. Neighbor did that on a WD9 and couldn't get it to start. To check you need to get the #1 cylinder on TDC and then check if rotor points to #1 plug. If it don't, re-install mag so rotor points to #1. Al
 

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