I tried Hotrod Lincoln's suggestion of clamping my hand down over the carb while the engine was running at 1000 rpms. Did this several times with no effect. Getting the engine temp up doesn't have any effect either. It just will die once I let my foot up off the gas. I currently have the carb apart. I studied the idle circuit in the manual and shot both compressed air and carb cleaner through the passages and they are clear. I did notice that the last time I rebuilt the carb, I had forgotten to put the spring into the discharge pump (the thing with the ball and the T shaped thing that guides a tiny spring). Everything else looks OK. I checked the manifold bolts and found most of them to be a bit loose. Not finger loose by any stretch but nowhere near tight, either. I also discovered that the terminal in the ignition coil had a good amount of corrosion. Another issue I have had for quite some time is an occasional cough out the carburetor on acceleration, which I created a thread on a while back. I never did solve this. Valves have been adjusted and operate freely. I know that a lean condition can also cause this. Anyway, I am soaking all the carb parts and will be rebuilding it with a new kit. I'm aware of the ethanol issue. I do use Stabil in my gasoline, if that makes any difference. Thanks for the responses. I will report back with how things work out.
