RB Concept engines, Instruction Manual

Page: 13 / 19

If however you prefer to try yourself, here is how:
Attention: Work only on 1 carburetor adjustment at a time and make
only small adjustments, maximum 1/8 of a turn!
Pre adjustments.
Once the engine is started let it reach operating temperature, then proceed
as follows:
1) Set the main needle by holding the car off the ground, then
open throttle completely. The engine should not completely clean out and
should stabilize at 80% of top RPM, but if the engine cleans out completely
and the rpm continues to climb too high, close the throttle immediately
and open the main needle and repeat the sequence, until the engine does
not clean out completely and the rpm stabilizes at 80%. If the engine runs
too rich (4-stroking aIl the way), lean the main needle until the engine just
starts to clean out.
2) Set the idle rpm of the engine by holding the car off the ground,
then open throttle till the engine rpm reaches the above rpm, and then
close the throttle. If the engine stalls, then you need to increase the idle by
turning the idle air screw clockwise until the engine does not stall anymore.
However, when the idle of the engine remains too high, then you need to
lower the idle rpm by turning the idle air screw counter clockwise.
3) Set the idle needle by holding the car off the ground, open the
throttle until the engine reaches the 80% rpm, and then close the throttle.
If the engine idles for 2-5 seconds and the idle rpm decreases, then the
idle needle is set too rich, so lean this setting by turning the idle needle
clockwise. Repeat this process until the engine has a constant rpm for at
least 20-30 seconds after the throttle has been closed. If the engine idles
for 2-5 seconds and then the idle rpm increases, the engine is running too
Iean at the idle needle, so richen the idle needle by turning it counter
clockwise to remedy this.
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