Rough running MTA

[bvaughn85]

Been working on an engine problem for awhile and looking for some other ideas. Engine started running rough while plowing with it. Thought it was possible carb issue. Rebuilt the carb and still same issue. Good fuel flow coming from tank. Gas is fairly fresh. Also tried a good working carb off another tractor to verify. Checked compression. All between 115 and 125. Changed manifold gaskets. Wondering if manifold could be bad but not really visibly seen? Still need to try the ether trick. Engine will smooth out with choke. I have an electronic ignition sitting in the shop but I’m just not convinced it’s an ignition problem. There was back feed from the alternator to the ignition switch but pretty sure that is fixed with the diode installed. Does anyone have other suggestions before I proceed?

 

[used red MN]

At what point do you think you will be convinced to look at the ignition components, when you’re steering it into the gate of the salvage yard? Changing the fuel mixture can affect how easily a plug will fire. Not saying you need electronic ignition, but some report of the condition of the plugs, points and spark plug wires. Rare problem on a Farmall but a weak valve spring could also cause this.

 

[caterpillar guy]

Well since it smooths out with some choke I would look at my fuel flow out the fuel line from the tank. then from the bottom of the carb if all is good then check the screen at the carb end of the fuel line. Though it would seem if the flow is good out the bottom of the carb that screen would be good also. If all tests good then it is time to look inside the carb for some dirt in a jet or passage. Once that is all proven good the next thing is ignition. all that is left. Now does the spark jump have a good blue spark do the plugs look clean like all are firing together. Or does one look sooty like it is notfiring on that cylinder well. Pictures of the plugs would tell a lot.

 

[Charlie M]

If it gets better with the choke I would look for leaks around the intake - something loose, hole developed in the manifold, bad gasket. I've heard going around with an unlit propane torch will also help find a leak. All this is free and easy - after that I'd be looking at ignition as mentioned above.

 

[wh]

Had a H do that once. Tried everything. A good mechanic friend told me i had a passage in carb clogged. Told me to try taking air hose off at carb. Start tractor and give it full throttle. Then clamp my hand over air intake and smother out. I did and it worked. Whatever was wrong got sucked on thru evidently. Tour mileage may vary.

 

[Brownie450]

Condenser might be getting "on the edge" of good. Be worth
putting a new one in to verify. Points also.
Maybe valves need adjusted also, but not likely.
Jim

 

[560Dennis]

If choking make it run better at idle ? Idle circuit is not functioning.
I suggest take the tune up, plug out of the intake and put a vacuum gage on it and see what you got Going on. Faster way of diag the problem.

 

[busboy]

Been working on an engine problem for awhile and looking for some other ideas. Engine started running rough while plowing with it. Thought it was possible carb issue. Rebuilt the carb and still same issue. Good fuel flow coming from tank. Gas is fairly fresh. Also tried a good working carb off another tractor to verify. Checked compression. All between 115 and 125. Changed manifold gaskets. Wondering if manifold could be bad but not really visibly seen? Still need to try the ether trick. Engine will smooth out with choke. I have an electronic ignition sitting in the shop but I’m just not convinced it’s an ignition problem. There was back feed from the alternator to the ignition switch but pretty sure that is fixed with the diode installed. Does anyone have other suggestions before I proceed?

When was the last time it had a tuneup, start simple, check plugs, points ect.