[Superglidesport]

318 with Onan P218G
Carb rebuilt, intake torn down and re-sealed.

There are 2 adjustment screws on the carb.

One is for idle RPM, I know how to adjust it.

I don't know what the other screw is called. It is the big one that is located on the front of the carb. It used to have a limiter cap installed on it.
Please tell me how to get that one adjusted correctly.

Thanks!

The idle speed screw opens the throttle plate slightly. The idle mixture adjustment is the screw you're referring to. They're usually preset and capped to limit tampering. I'd start it at 2 - 2 1/2 turns out. Run the engine until it's warmed up, then turn the screw in or out until the idle increases and maxes out. Then, turn the screw clockwise to reduce the rpm slightly, 50-75 rpm, set your final idle speed to spec with the throttle plate adjustment screw and that's about it.