OFNA Racing Ultra MBX R2 - Manual (Page 30)

ENGINE BREAK-IN AND TUNNING
(BREAK-IN THE ENGINE BEFORE DRIVING THE CAR!)
OPTIONAL OFNA CAR STANDS IN 4 COLORS
TUNING AFTER BREAK-IN USING A FORCE .21 ENGINE
Idle adjuster screw &
Barrel Stop
Lean
Rich
• Choose a wide clear outdoor location with low dirt and dust.
• Set the car on box or holder with wheels off the ground.
• Turn on radio and car. Make sure throttle is at idle position.
• Fill fuel tank and set master engine needle.
• Prime fuel line and Heat glow plug before pull starting engine.
• When started, let engine fast idle for two tanks of fuel.
Close master needle by turning clockwise until it stops.
Then open needle by turning counterclockwise 3 turns
(rich setting).
When running car, adjust carb with 1/8 clockwise turns,
slowly leaner, until the top speed good. Check engine
temp, if possible, for no more 250 degrees.
Adjust barrel stop so it will not close, accept for a small gap.
This gap will be the idle setting. You will notice the idle will
increase with a wide gap.
Adjust low end needle for best throttle response. Use only
small turns. From idle, give it full throttle, if throttle is slow
lean out needle until good.
WOOD BLOCK