it didn't come with a wrench when you got the car?
normally, you get a whole tool kit when you buy the car.
if the glow plug is bad, the engine won't start at all. the glow plug either works or it doesn't (like a lightbulb).
it still may be running too rich...too much fuel getting into the engine. while the ignitor is hooked to the glow plug, the plug will glow and be able to get the fuel burned. remove the glow plug ignitor and there may be too much fuel for the engine to burn by itself. these motors run on compression, the glow plug is just to get it started and help build a little heat in the motor.
is the linkage on your servo going to the carb set up right?
if it isn't the servo will actually pull the carb closed past your idle setting and kill the engine.
you have to set the idle with the idle screw on the carb. not with the trottle trim in the radio.
on the carb linkage, loosen the little hex stopper thing, and pull the carb arm all the way closed with your fingers ( move it towards the rear of the car) and then tighten the hex stopper thing back down.
that may not be the problem but it's possible.