JD A carb problem continued..still need help.

As soon as it dies, I'd pull the spark plug wire, hook it on a spare plug and turn it over to see if you still have fire, both sides?

Sounds almost like an intermittent coil. And yes they do make those for magnetos too. :)

~Before you can set the starting timing you must have the flywheel on correctly, so check the flywheel to crank position. Then to check it, just slowly rotate the flywheel in the running direction [CCW] & watch the L/H impulse mark on the flywheel as it comes up to the case timing mark [a 3 o'clock behind the flywheel & at the same height as the crank center], when the mag snaps the L/H impulse text on the flywheel should be right at that case mark. If not, loosen the mag & rotate the top of the mag forward to retard the timing or rearward to advance the timing... Another way to set the starting timing is to keep moving the top of the mag to the rear until the flywheel kicks backwards when it fires while starting, then rotate the top of the mag forward until the kicking back stops [at that point you are as advanced as you can be for starting].

~We can talk you through setting the lag angle [running timing] on your mag but will have to know what mag & what the impulse cup number is. To get it close enough for it to run pretty good, pull the mag out & turn it so the impulse cup is facing you, then look at the impulse stop ring, the impulse pawl stop MUST be on the left [if not loosen the stop ring screws & turn the ring so the stop is on the left, then set the stop ring witness mark at 2-1/2 marks left of the center [straight up] case mark. That could be off a little if you have a 25� impulse cup on it but should be close enough to get it started & running pretty good. With your set up you will probably want to set the running timing when it's on a dyno anyway.

~If you are getting a blue spark at the plugs like you say & if the mag is tripping when the L/H impulse is lining up with the case mark it probably doesn't have a spark problem. It is easy to miss something in that carb so just because you have been into it a few times doesn't mean there isn't a problem with it. Are you sure the main well fuel hole in the side of the stem is not rusted shut? That hole is next to impossible to see if it is rusted shut & will cause a problem like you have.

~If you are sure you are getting a good spark, at the correct time, & the carb is functioning correctly with a working choke, you have other problems. You might want to check the cam timing against the [L/H ex open] on the flywheel [you will have to ask your cam grinder where it should line up]..

~Keep us posted on your progress & if you find anything....

Good Luck Ol John T Nordhoff

1. Based on limited info, as you say it runs a while but not long, that tends slightly more to fuel starvation than an ignition problem, but its still too early to tell. It sounds like the carbs float and bowl and needle valve/seat are okay, and clogged idle passages can cause poor idle, but she should still not just simply run then totally quit as you indicate. When you say you cleaned the carb, were the brass drill plugs removed and those passages driled out the proper size and all side and smaller subsidiary passages cleaned out also????? And was the center vertical brass nozzle removed and cleaned including all its tiny small side holes???

2. When she starts to die, does it sputter n smoke (what color out the stack????) and will choking her help any or make much difference???? Or does it act like the ignition was suddenmly turned off????? ? It would help if immediatley after she died, you checked if it still had a good blue spark, and if the plugs are wet or dry and what color or deposits are on them ????? ???? 3. What type of ignition do you have (mag or distributor) and what shape are the points and their gap in, and do you have good solid wire core wires and clean good plugs??? If you remove the plugs and leave their wires attached with their frame against the tractors steel and crank her over, does each produce a good visible blue spark or a faint wimpy yellow one???

4. Also, as in the JD 70 post below, you may want to check for vacuum leaks. Have you looked at the air cleaners bowl lately????? ?? and is the choke butterfly plate actually opening and closing in relation to where the exterior choke rod is at????? ?

More could be said, but we need to try and see if its a fuel starvation or ignition related problem if possible, as ignition problems can cause simuilar symptoms at times.

Play with her a bit and see what kind of spark youre gettign at each plug and let us know. Good Luck n God Bless Ol John T Nordhoff