OFNA Racing 12 S,15 S User Manual
#57076
Slide Carburetor, complete
#57038
Screw set
NEW!
#57001
Head, tall (blue)
#57001A
Head, flat (black)
#57063
Head, tall (gray/black)
#57073
Head, tall (silver)
#57029
Main
#57016
Barrell Carburetor, complete
#57015
Body, carb.
#57024
Screw, stop
#57023
Spring, stop
#57038
Seals, low end
#57018
Throttle needle,
mid range
#57020
Boot, throttle
#57021
Lever, throttle
#57022
Nut, throttle
DO NOT SEND ENGINE FOR REPAIR UNLESS YOU DO THE FOLLOWING..
• ENGINE MUST BE ASSEMBLED, NOT IN PIECES.
• ENGINE CASE MUST BE CLEAN WITH NO OUTSIDE GREASE OR DIRT.
• ENGINE ACCESSORIES, i.e. FILTER, CLUTCH AND PIPE MUST BE REMOVED.
SEND TO:
OFNA RACING
22692 GRANITE WAY, STE. B
LAGUNA HILLS, CA. 92653
TEL: (949) 586-2910
#57027
Supply
nipple,
plastic
#57014
Barrel
#57019
Spring
#57014
Drvie hub
#10330
Brass corn
needle
#57035
Seal, main needle
#57028
Main seat
#57034
Seal set
$57033
Seal, carb.
#57030
Bearing, outside
#57013
Cap screw, plug
#57039
“G” clips
#57025
Low end needle
#57031
Bearing,
inside
#57002
Head button, .12
#57003
Head button,.15
#57064
Head button,.17
#57004
Head shim, .12
#57005
Head shim,.15
#57065
Head shim,.17
#57036
Pin, piston, .12
#57037
Pin, piston, .15/.17
#57039
#57008
Rod, stock
#57075
Rod,
special
“G” clips
#57009
Crankcase, .12 or .15
#57074
Crankcase, .12 pro
#57012
Carb. set pin
FORFOR
FOR
FORFOR
& .12S PR& .12S PR
& .12S PR
& .12S PR& .12S PR
#57001A
Head. flat
(black)
#57006
Piston/Sleeve, .12
#57007
Piston/sleeve,.15
#57062
Piston/sleeve,.17
#57070
Piston/sleeve,.12 pro
#57061
Spring and pin
(small dia.)
#57010
Crankshaft, .12 or .15 (large hole)
#57060
Crankshaft, .12 or .15 or .17 (small hole)
#57071
Crankshaft, pro (small hole)
CE .12SCE .12S
CE .12S
CE .12SCE .12S
#57039
Seal, rear cover
,,
.15S .15S
,
.15S
,,
.15S .15S
O ENGINE DRAO ENGINE DRA
O ENGINE DRA
O ENGINE DRAO ENGINE DRA
DO NOT SEND ENGINE FOR REPAIR UNLESS YOU DO THE
FOLLOWING..
• ENGINE MUST BE ASSEMBLED, NOT IN PIECES.
• ENGINE CASE MUST BE CLEAN WITH NO OUTSIDE
GREASE OR DIRT.
• ENGINE ACCESSORIES, i.e. FILTER, CLUTCH AND PIPE
MUST BE REMOVED.
#57040
Back plate assembly,
complete
#57011
Rear cover
#57038
Screw set
,,
.17S .17S
,
.17S
,,
.17S .17S
#57042
One-way
breaing unit
Can’t rebuild
WINGWING
WING
WINGWING
#57049
Pull start unit, complete
FORFOR
FOR
FORFOR
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 WASHERS.
CE .12SCE .12S
CE .12S
CE .12SCE .12S
,,
.15S CARB .15S CARB
,
.15S CARB
,,
.15S CARB .15S CARB
URETURET
URET
URETURET
OR SETTINGOR SETTING
OR SETTING
OR SETTINGOR SETTING
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..
NEW! EASY TUNE TWO NEEDLE CARB.
LOW END NEEDLE IS ON
OTHER SIDE OF CARB
BODY.
SMALL GAP
Carb. barrel picture, showing
low end needle setting in a
fully open position.
Factory 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
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