'73 400 idle/low speed problems

[Caleb55]

I sold a guy I work with a '73 John Deere 400 last year so he could ride it around his woods. The issue he's having is ideling issues mainly. I had him pickup a carb kit, which apparently just includes gaskets and diaphrams as that's at that was in it. I tore the carb apart last night and cleaned everything and put the new gaskets in. Once started, you have to feather the throttle to keep it running. I took it for a quick spin and it will acclerate fine, and run fine as long as your giving it moderate to heavy throttle. Once you let off the throttle for a few seconds it will start to spudder and you have to play with the throttle to keep it going. Sometimes it will stall out completely. After stalling, it will be hard to start (about 10 pull or so) before it takes back off. I feel bad about it not running right for him and want to get it dialed in. What should I be looking for to cure this problem?

[Matt]

The Walbro has a separate low speed circuit, so I would start there. As far as adjustments, you're supposed to set the idle first with the stop screw on the throttle lever, then adjust the low speed screw on the side of the carb to get the smoothest idle.

Webman has the Walbro WDA , WD, WR tech manual on his web site, that might help you understand the carb a little better then the Deere manuals do:
http://www.vintagesnow.com/Carburetors.html