Jl .21 pro engine – OFNA Racing JL .21 Pro User Manual
Page 3

8MM CAR B U R E TOR ADJU S T ME NT S
IDLE
GAP
-
fig.
1,
FACTORY
SETTING
-
.5mm
(.20)
ID L E SC R EW
This special carburetor has the high heat nylon body to counter act heat
from the engine that may boil the fuel before entering the engine. Over
heated fuel causes tuning problems that are hard to resolve. This new
design will give you much better performance.
Master Needle
3.5 turn out from
close.
Low end needle
fig. 2
JL .21 PRO ENGINE
FIG 1
Adjust idle screw to
Increase or lower engine idle. Never let
barrel fully close or adjust idle from only radio.
LOW END NEEDLE - Shown fig. 2 is the Low End Needle, which is
preset by
. You can adjust this needle after break-in if needed.
When turning this needle, make only small 1/16 turns.
FACTORY SETTING - TURN IN UNTIL STOPS, DO NOT OVER
TIGHTEN. TURN COUNTER CLOCKWISE
TURNS
OFNA
4
.
MASTER NEEDLE - Adjust this needle for best power and temp. The preset
setting should be
TURN OUT. It is recommended to turn this needle "OUT"
during break-in (richer mixture) if engine is too hot.
3 ½
FACTORY SETTING