RCGF 21CC-Twin Operator's Manual page 14

(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
internal engine components.
Carburetor Adjustment Troubleshooting
Problem:
If The engine hesitates when accelerated rapidly.or The rpm increases at idling. or The
engine stops when the throttle is moved from high to low.
Solution:
The low-speed needle "L " is too lean. Open it up about 1/8 of a
turn and try again.
Problem:
If The idle is not steady.
Solution:
The low-speed needle "L " valve is too rich. Close it 1/8 of a turn
and try again.
Problem:
If Engine stops at full throttle.
Or Engine hesitates when accelerated rapidly.
Or The engine will not come up to full rpm at full throttle.
Solution:
The high-speed needle valve "H" is too lean. Open it up 1/8 of
a turn and try again.
Problem:
If Your engine does not reach full rpm.
Or Carbon build-ups appear consistently on your spark plug.
Solution:
The high-speed needle valve "H" is too rich. Close it up 1/8 turn
and try again.