O.S. Engines 21VZ-B V-Spec - Manual (Page 18)

Turn the needle-valve clockwise slowly until
it stops. This is the fully closed position.
Do not force to turn further.
Open the Needle-Valve 3 turns from the fully
closed position.
Switch on the transmitter and receiver and
set the throttle very slightly open from the
idling position.
Needle Valve
Open
Throttle opening at idling
approx 0.3-0.5mm
Close
Note:
Throttle opening at idling should be
checked before fitting an air cleaner.
Turn the engine with starter box to draw the
fuel into the engine.
Starter Box
Deliver fuel into the carburetor.
Fuel tank side
Fuel
17