Did you do all of that work because it was stalling at throttle-up? Or did it start after you started replacing parts?
First, check for fuel. Get a can & put it under the carb. Remove the bolt in the bottom of the carb; as long as the fuel is turned on, you should see gas flowing out of the carb. It should fill a pint jar in less than 2 minutes. If it?s a dribble, or runs for 5 seconds & stops, or none at all, you have solved half the problem: it?s fuel related. If gas flows well out of the carb & only stops when you turn it off at the sediment bowl, chances are very good it?s not a fuel problem.If it does not have gas coming out of the carb at a steady stream w/ the bolt out for at least 30 seconds, you have a fuel problem. First, remove the gas cap. Your vent could be clogged & it vacuum locked. If that doesn?t work, tap the carb bowl w/ a hammer handle in case the float is sticking closed. (don?t whack it w/ the head of the hammer; you can crack the bowl). If you still don?t see gas flowing, the N has three fuel screens; one in the brass elbow, one in the top of the sediment bowl & one on the stem of the sediment bowl in the gas tank. (see tip # 45) Check the screen in the elbow (see tip # 56) & the screen in the top of the sediment bowl. (don?t worry about the one in the tank) Both probably need to be cleaned. If you have the fuel knob turned on all the way, & 1 gallon or less in the tank, it may be trying to feed off of the reserve inlet which is probably clogged. Only open it 2 full turns. Put at least 2 gallons in the tank. (and do not forget to turn the gas off; see tip # 9)
If fuel flow is ok, adjust the carb.
Make sure the tractor is at operating temp; that usually takes 10 ? 15 minutes at idle depending on ambient temp.
Both Ford and Marvel/Schebler (assuming you have a M/S carb ) say to set both the side-pointing idlemix and the down-pointing mainjet to 1-turn as a starting point. I set the down-pointing mainjet to 1-1/2 turns and don't fool w/ it until the final step.
Then adjust the side-pointing idlemix for fastest idle; not the smoothest idle. Next, adjust the behind the carb idle-speed set-screw for very slow 400-rpms idle. Do that idlemix adjust for maximum idle at least 3-times. Make sure that you turn the screws slowly, like 1/8 of a turn at a time & wait a second or two for the engine to catch up. Take your time!
Do it like this:
1. Adjust idle mix jet until RPM increases
2. Adjust idle-mix set screw until the engine nearly stops (as slow as you can get it unless you have a tach that tells you 400 rpm)
Repeat steps 1 - 3 three times.
Remember the side-pointing idlemix is out for lean, in for rich.
If you do not have any problems inside the carb, it is easy to get the idle down to 350 - 400 rpms.
Your last step is to go back to the main jet. Remember, in for lean, out for rich. If you end up turning it OUT more than ? turn for max power (remember, you already had it 1 ? turns out) then stop right there because you have a dirty carb or a fuel problem.
75 Tips
