Farmall. 300

Anonymous-0

Well-known Member
I was using my 300 to plow snow this am,after running about 45 minutes the engine runs at full throttle all the time. It will not slow down. A friend said some have a nylon connection in the throttle linkage,that could have broken.any ideas? Thanks in advance.
 
No nylon to my knowledge. If it was wet snow at about the freezing point, the throttle plate could have iced up and stuck. Does wide open mean over revving, or just not going to idle. Over revving has the engine turning beyond full throttle speeds, Not good.
A stuck throttle or linkage off of the throttle lever getting stuck at full throttle is different.
If that were the case, it would operate fast, but no faster than normal full throttle. it would be able to sense loads and change throttle position but stay at the normal high speed.
If runaway speed, the throttle either stuck in the carb (shaft or loose plate getting jammed), or the tab in the linkage at the inside of the governor tube to carb fitting broke off. Jim
 
Jim,Some of the newer carb kits now have a nylon/plastic piece on the throttle shaft where it connects to the governor.
 
I had that issue with my H and it turned out to be a governor problem. Mine was OK when the weather was warm but not in the cold. I never figured what was wrong with the governor but for other reasons I had to change out the unit and it worked fine after that.
 
Also condensation in the tube between carb and governor. If you take out the idle speed adjustment screw and squirt heet, or penetrating oil in that may prevent it from happening for a while. Always been a problem with that set up from H to 450's.
 
It is common for ice to form on the exterior ( and interior) of the carb in these conditions, causing linkages & the butterfly to stick. Should be fine after it thaws out. Let it idle for a time when this happens, or cover part of the front radiator to circulate the heat from the manifold, or use a heat houser.
 
Ran into that one winter myself. I had a heat houser on it and had it parked under a a tarp, much like the portables that are big today. It would start up alright but then as you say it would stick in its normal wide open, not over speeding, throttle. Once it run awhile and got good and warm it would ultimately slow back down to idle and be fine the rest of the day. Pulled back the tarp from the carb and I could see the side of the block was all frost. Ever since I make sure I make room for it in the machine shed. Still no heat but alot drier air and haven't had any issues with it since.
 
IH decided the original 300 and 400 manifolds could use more help for that problem in cold weather operation. They made a attachment block that could be mounted on those manifolds to heat the intake more. Hard to find now.
 

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