how did you get it to idle at 50? and how did you measure it?

500 yeh, ive had my thou down around there somewhere when cold... it fouled the plugs up tho

750 is the optimum idle for a new small 4cyl carby engine.

just adjust the mixture untill you get the smoothest idle, then slowly bring the idle speed down too. Make sure its running as smooth as it can and not trying to stall because its too low. And no it doesnt sound like a V8... it sounds like a pooly tuned 4pot!