Modern Vespa

Hey guys,
on my allstate's carb, the left side (sitting facing the engine) on the bottom right above the gasket where it mounts to the engine there is a small brass screw with a spring over the threads to keep it in tension i assume. what is that screw for? there is a plastic "plug" in the carb box that can be unscrewed so that screw can be accessed without taking the carb off. thanks-Todd

that the air fuel mixure screw. it controls the mixture at and just off of idle until you get into the diffuser and main.

depending on the carb and your set up, you should have that screw at about two turns out. basically, you want the best tick-over and for it to return to idle without lagging.

oh, yeah, and don't over tighten it. bad things happen.

best,
greasy

cool thanks, I was thinking it was that due to the needle shaped end.
the scoot is finally running right