OFNA Racing Force .12 S & .15 S - Manual (Page 2)

FOR FOR FOR FOR FORCE .12S CE .12S CE .12S CE .12S CE .12S,,,,, .15S CARB .15S CARB .15S CARB .15S CARB .15S CARBURET URET URET URET URETOR SETTING OR SETTING OR SETTING OR SETTING OR SETTING
MASTER NEEDLE -
STARTING = 2.5 TURNS
BREAK-IN = 2.5 to 3.5 TURNS
WORKING = 1.5 to 2.5 TURNS
LOW END NEEDLE (JET)
PRESET = FLUSH
Carb. barrel picture, showing
low end needle setting in a
fully open position.
Factory setting
LOW END NEEDLE IS ON
OTHER SIDE OF CARB
BODY.
NEW! EASY TUNE TWO NEEDLE CARB.
SMALL GAP
THE CARBURETOR IS FACTORY SET FOR THE LOW END NEEDLE, SO DO NOT ADJUST UNTIL BREAK-IN
IS COMPLETED. BUT YOU MUST ADJUST THE MASTER NEEDLE BEFORE STARTING.
ADJUSTMENTS
1) MASTER OR HIGH END NEEDLE - THIS ADJUSTS THE MAXIMUM SPEED OF THE CAR WHEN THE CARB IS FULLY OPEN. AFTER BREAK-IN IS COMPLETED, THE
NEEDLE SHOULD BE 1.5 TO 2.5 TURNS OUT. TURNING THE NEEDLE IN (CLOCKWISE) IS LEANING OUT FUEL MIXTURE AND INCREASES HEAT. SO, TURNING OUT
NEEDLE ( COUNTER CLOCKWISE) WILL RICHEN THE MIXTURE AND REDUCE HEAT. THE HEAT OF THE ENGINE SHOULD BE AROUND 250 DEGREES, LOWER IS
BETTER, BUT HOTTER IS BAD.
FOR BREAK-IN, TURN MASTER NEEDLE OUT 2 TO 3+ TURNS TO KEEP FUEL MIXTURE RICH AND KEEPING ENGINE RPM LOW. LET THE ENGINE FAST IDLE, CAR AND
WHEEL OFF THE GROUND, FOR AT LEAST ONE TANK OF FUEL. RUN THE CAR ON THE GROUND AT A SLOW/MEDIUM UP AND DOWN SPEED FOR ANOTHER FEW
TANKS. AFTER RUNNING THE ENGINE FOR A FEW TANKS OF FUEL, TURN NEEDLE SLOW IN (1/4 TO 1/2 TURNS) FOR EACH PROCEEDING TANK.
2) LOW END NEEDLE (JET) - THE LOW END NEEDLE CONTROLS THROTTLE RESPONSE. AFTER BREAK-IN, IF THE ENGINE THROTTLE RESPONDS WITH SLIGHT A
DELAY, TURN THE LOW END NEEDLE CLOCKWISE (1/8 TO 1/4) TO LEAN OUT MIXTURE. TRY TO USE SMALL 1/8 TURNS. FACTORY SETTING IS FLUSH, SEE FIGURE.
3) BARREL STOP / IDLE SCREW - THE SCREW MUST ALWAYS BE SET SO THE BARRELS DOES NOT FULLY CLOSE. LEAVE A SLIGHT GAP, THIS IS YOUR ENGINE IDLE.
A LARGER GAP WILL INCREASE IDLE, BUT ALSO, CHANGE LOW END SETTING. THEREFORE, YOU MUST WORK BACK AND FORTH WITH BOTH NEEDLE.
GLOW PLUG: ENGINE IS DESIGNED FOR A SHORT STYLE GLOW PLUG, SO USE O.S. 8 GLOW PLUGS. IF YOU WANT TO USE McCOY PLUGS, USE AN MC-59 WITH
TWO COPPER WASHERS TO PREVENT DAMAGE. IF THE MC-59 IS NOT RIGHT FOR YOUR AREA, MC-8 OR MC-9 CAN BE USED ALSO BUT WITH TWO COPPER WASH-
ERS.
FUEL: 20% FUEL IS RECOMMENDED, i.e. BYRONS; BLUE THUNDER, O’DONNEL. OTHER FUEL MAY CAUSE VARIOUS PROBLEMS SO BE CAREFUL WHEN BUYING
FUELS OTHER THAN MENTIONED..