51 John Deere A: Issues Under Load

Hi All. I have been looking around on the forums for a good while as I have chased a few issues with a model A this summer. I haven't really came across someone with exactly the same issue that I'm seeing and was hoping that you guys could give me some pointers. I apologise for what will be a rather long post.

The issue is, the tracor will idle fine at any throttle speed. Will run good under load while bush hogging or such. But, stumbles really hard when load is applied like starting off from stop and beginning to accelerate in a higher gear or if starting on a hill. It also seems to do it much worse when it is hot, sometimes to the point of not being able to get going. You will have to tease the clutch in and out just to keep it from stalling out until up to speed. But then it is fine. It will climb a steap hill in 6th gear with out any issues if already up to speed.

I recently went through the ignition changing the coil, condenser, rotor, and points and plugs. It is the Wico XB system. A friend did mention that the rotor cap was worn but have not got a new one yet. These parts were changed as result of suddon onset of the tractor running bad, cutting off, and not restarting.

Any ideas, thoughts, or suggestions are highly appreciated as I'm not exactly sure where to go from here and don't want to start just changing parts. Tractor show season is coming up and I'm wanting to get it back in good running shape

Thanks in advance for the help!

I'd make sure the load circuit in the carb is not plugged up and run a compression test

Try adjusting the load needle or your carb needs cleaning. Ron MN

The main nozzle in the carb. acts as an accelerator pump holding gas in reserve in the space around it. The passages in the nozzle could be clogged. But first see if the idle screw is too lean and open it up some and see if that helps.

Mike is on the right track, it sounds like your acceleration well is not storing up enough fuel.

The load nozzle is not pushed in all the way to be seated. If you look in end you will no doubt see that the brass nozzle tip is NOT sticking up in throat 3/8" - 1/2". I just did one for a customer with the same issues. Everything else worked fine...just would not accelerate quickly. I've never seen one actually plugged yet. I've seen many not in far enough. This last one , the customer built and put in a nice new nozzle. They drop in so far but usually need a few taps with a small driver and hammer to finally go down and seat. No one wants to hammer on a nice new nozzle but that's what it needs and will not hurt it. Will act same as being plugged. The load fuel cannot get to the top because the "straw" is not protruding up in the air stream . I've seen them in upside down also...does same thing. Once you baby it it will get going but if you throw throttle open ..it will die.