1. Choke Control (the choke control should be used when the engine is cold)
2. Throttle
3. Idle Adjustment Screw (adjust the idle speed)
4. (L) Low-speed Needle (adjusts the fuel/air mixture at low speeds)
5. (H) High-speed Needle (adjusts the fuel/air mixture at high speeds)
Idle Adjustment
Turning the Idle Adjustment Screw clockwise will increase the idle speed. Turning the Idle
Screw counter-clockwise will decrease the idle speed.
Low Speed Needle Adjustment
Turning the Low-speed Needle clockwise will lean the fuel/air mixture at low speeds.
Turning the Low-speed Needle counter- clockwise will richen the fuel/air mixture at low
speeds. (The default or factory setting of the Low-speed Needle is as follows: turn the
needle to the fully stop/closed position and then turn back 0.8 turns.)
High Speed Needle Adjustment
Turning the High-speed Needle clockwise will lean the fuel/ air mixture at high speeds.
Turning the low-speed Needle counter-clockwise will richen the fuel/air mixture at high
speeds. (The default or factory setting of the High-speed Needle is as follows: turn the
needle to the fully stop/closed position and then open the needle 1 turns). It is
recommended that the High-speed needle be adjusted by the use of a tachometer to
obtain maximum speed. Smooth acceleration and deceleration is an indicator of proper
engine performance.
Ignition Timing Adjustment
The ignition timing is preset on the RCGF120cc twin at 28-30° before Top Dead Center
(TDC). The ignition timing can be advanced or retarded by loosening the ignition sensor
Phillips head screws and sliding the sensor to the full extent clockwise (32° advancing
the ignition) or counter clockwise (26° retarding the ignition). Be sure to retighten the
Phillips head screws after adjusting the ignition timing. It is best to attach the sensor with
the screws centered in the slot as a starting point.
Advancing the timing causes combustion to occur earlier resulting in
higher performance of the engine. However, advancing the timing also
causes higher engine temperatures and can cause premature wear of