Move your throttle lever back and forth and watch what moves inside the engine compartment. Usually at least one of the levers that move....one is for carb butterfly control and the other is for timing changes, sets the engine timing to set the idle speed (on some engines like mine) and the other would be a stop for controlling the amount the carb's butterflies move.
On my engines, idle speed of 650 RPM was set by the timing adjustment around 0 degrees. The screw on that arm extending up from the throttle control is used for setting the idle speed minimum advancement. The lever upon which this adjustment screw is attached, extends to components up under the flywheel for controlling the timing of the stators to the magnets on the flywheel and at WOT the timing will be 20-24 degrees BTDC, much earlier than that required at idle.