Have an older RCS 140 that will not idle right when the engine is warm no matter what the carb idle mixture is set at, It will run fine top end but as soon as it gets warm it seems to go lean and die. to restart you must choke and flip 6 or 8 times then go to full throttle to kind of purge the carb. Seems the carb. is getting warm and then not delivering fuel till it cools off. Wonder if this might be a problem with the original 140's, maybe not enough heat isolation between the crankcase and carb. Any thoughts would be appreciated.

Maybe the carb is located in hot air. That is all to easy in rear carb engines.