Hoping it was what TLC mentioned, but since no difference only other thing I can think of is checking the intake manifold for any cracks/air leaks,etc that could cause it to die. Runs good but doesn't idle(carb jets are clean as you said) and adjusting idle doesn't help on carb,but doesn't back fire(usually sign of lean running) and hard to start after you kill it. I'm still down to either air leaks, tight valves, battery (is charging good back to the battery,14 volts?) or ignition system getting weak? OPT

 

So can something in the electrical system cause the problem? Never thought about that. Although I just put a brand new Yuasa battery in it about a monh ago.
I guess I always thought it was like a car....once it's started it doesn't use the battery anymore.

 

Main thing is that it's charging 14 volts back to the battery while running. Must have a constant 12 volts for everything to operate. No different than a car. Just a process of elimination,if the battery and spark is good,go on to the next thing such as the carb and eliminate it as a problem,then check out the valve clearance,etc. OPT