First off, where is the gauge hooked up at? It must be below the throttle blades, if its above them, you will get a bad reading. Just look at the position of the port you are using, is it above or below the throttle shaft?
Retarded timing will cause it to get hot, start advancing the timing till the engine perks up, reduce the rpm at the carb if need be and keep playing with the timing. You will need to go back and forth from carb to timing. Once you are happy with the timing, adjust the idle mixture screw in till the engine starts to run bad and slow down. Back it out somewhere between 1 to 2 turns. You may have to go back to the timing and rpm after adjusting the carb as each setting effects the other.
The vacuum gauge is nice, but it must be hooked to direct vacuum. Timing lights help too.
If you advance the timing to far, the starter will struggle and you will get detonation when pulling a hill or under a decent load. Again, there is that fine line you need to stay around or under.
A computer controlled engine will keep the fuel mixture as lean as it can with out damage to the engine and the timing right at or below the detonation point. That is the ideal emissions and fuel economy settings, a computer can change them hundreds of times a minute. With a carburetor and set and forget timing, you need to find a happy medium and hope for the best.
Joe
