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4

Take care that the glow plug clip or battery leads do not come into contact with the propeller. 
Also check the linkage to the throttle arm. A disconnected linkage could also foul the propeller.

After starting the engine, carry out any needle-valve readjustments from a safe position behind the rotating 
propeller. Stop the engine before attempting to make other adjustments to the carburetor.

Adjust the throttle linkage so that the engine stops when the throttle stick and trim lever on the transmitter are fully 
retarded. Alternatively, the engine may be stopped by cutting off the fuel supply. Never try to stop the engine 
physically.

Take care that loose clothing (ties, shirt sleeves, scarves, etc.) do not come into contact with the propeller. 
Do not carry loose objects (such as pencils, screwdrivers, etc.) in a shirt pocket from where they could fall through 
the propeller arc.

Do not start your engine in an area containing loose gravel or sand. The propeller may throw such material in your 
face and eyes and cause injury.

For their safety, keep all onlookers (especially small children) well back (at least 20 feet or 6 meters) when preparing 
your model for flight. If you have to carry the model to the take-off point with the engine running, be especially 
cautious. Keep the propeller pointed away from you and walk well clear of spectators.

Warning! Immediately after a glowplug-ignition engine has been run and is still warm, conditions sometimes exist 
whereby it is just possible for the engine to abruptly restart if the propeller is casually flipped over compression 
WITHOUT the glowplug battery being reconnected. Remember this if you wish to avoid the risk of a painfully rapped 
knuckle!

NOTES

5

INTRODUCTION

Rocker Cover

Cylinder Head

Push Rod Cover

Drive Hub

Propeller Washer

Propeller Nut

Lock Nut

Intake Pipe

Carburetor
Type 60U 

Glow plug Type F

Crankcase

INSTALLING THE GLOW PLUG

Glow plug

Carefully insert plug, with washer, 
fingertight only, before final tightening 
with the correct size plug wrench.

Washer

Beam Mount

The FS-70 ULTIMATE comes equipped with the new O.S. FS-
70U diaphragm type fuel pump and matching Type 60U carbur-
etor incorporating a built-in pressure regulator. These features 
ensure that fuel/air mixture strength is maintained at a constant 
level through maneuvers, for consistent performance and reli-
able throttle response.
In the interests of improved durability, certain ferrous parts that 
are particularly susceptible to corrosion in four-stroke engines, 
have a corrosion resistant plating and, for the same reason, a 
special grease-packed twin-sealed rear ball-bearing is used.
To maintain the four-stroke engine's reduced noise levels, the 
FS-70 ULTIMATE is supplied with an O.S. Type F-4020 baffled 
silencer (muffler) of substantially enlarged volume, as standard 
equipment. 

Where installation calls for a separate exhaust pipe, these parts 
are available as optional extras.

Crankshaft

Pump Unit (FS-70U)

Summary of Contents for FS-70 Ultimate

Page 1: ...control equipment etc are accessible for checking at the same time 1 2 4 5 6 7 8 9 10 11 12 13 14 SAFETY INSTRUCTIONS AND WARNINGS ABOUT YOUR O S ENGINE INTRODUCTION INSTALLING THE GLOWPLUG INSTALLATION FUEL TANK LINES EXHAUST HEADER PIPE AND SILENCER THROTTLE LINKAGE NEEDLE VALVE EXTENSION CARE OF FUEL PUMP AND REGULATOR PROPELLERS GLOWPLUGS FUEL PROPELLER AND SPINNER ATTACHMENT TYPE 60U CARBURET...

Page 2: ...your engine in an enclosed space Model engines like automobile engines exhaust deadly carbon monoxide Run your engine only in an open area Model engines generate considerable heat Do not touch any part of your engine until it has cooled Contact with the muffler silencer cylinder head or exhaust header pipe in particular may result in a serious burn 3 NOTES This engine was designed for model aircra...

Page 3: ... glowplug ignition engine has been run and is still warm conditions sometimes exist whereby it is just possible for the engine to abruptly restart if the propeller is casually flipped over compression WITHOUT the glowplug battery being reconnected Remember this if you wish to avoid the risk of a painfully rapped knuckle NOTES 5 INTRODUCTION Rocker Cover Cylinder Head Push Rod Cover Drive Hub Prope...

Page 4: ... nut firmly down onto first nut Tighten this nut first Steel washer 3mm steel nuts 3mm steel screw Spring washer or lock washer 15mm min 15mm min Hardwood such as cherry or maple Spring washer 3mm steel Allen screw 7 FUEL TANK LINES 10 15mm A fuel tank of approximately 300cc capacity is suggested This allows up to 12 13 minutes flying time dependent upon the type of fuel used the size of the prope...

Page 5: ...throttle stick is in its fully open position Carefully align the appropriate holes in the throttle arm and servo horn so that they move symmetrically and smoothly through their full travel Install these in the following sequence Screw the header pipe into the cylinder head until it bottoms then unscrew sufficiently to achieve the desired exhaust angle and tighten the locknut securely with a 14mm w...

Page 6: ...small percentage 5 30 of nitromethane for improved flexibility and power The carburetor is adjusted at the factory for a fuel containing 20 lubricant and 15 nitromethane Some commercial fuels also contain coloring additives as an aid to fuel level visibility In some cases these additives have indicated slightly negative effects on performance We would suggest that you use such fuels only if you ar...

Page 7: ... fast enough to cause the fuel pump to prime the cylinder automatically Starting procedure is as follows Check that the current to the glowplug is switched off Check that the polarity of the starter battery leads rotates the engine counter clockwise when viewed from the front Open the needle valve approx 2 turns from the fully closed position and temporarily set the throttle in the fully open posi...

Page 8: ...ightly rich 30 45 from the highest r p m setting Close the throttle to the idle position Allow the engine to idle for about 5 seconds then reopen the throttle The engine should accelerate smoothly back to full speed If instead the engine responds sluggishly and emits an excess of white smoke from the exhaust the idle mixture is too rich Turn the mixture control screw approx 45 clockwise to lean th...

Page 9: ...ount of running time a loss of power is detected or if the engine has been disassembled for repair these clearances should be checked and reset as necessary VALVE ADJUSTING The kit comes in a plastic case and includes Code No 72200060 Feeler gauge 0 1mm Hex key 1 5mm Wrench 5mm 17 Re tighten locknut while holding adjusting screw stationary Fig 5 4 Hold at the screw head Fig 5 Tighten Locknut Remov...

Page 10: ...le valve assembly from the carburetor and remove any foreign matter that has accumulated in this area See photo If these precautions are neglected restriction of fuel flow may cause the engine to cut out or the fuel air mixture to become too lean causing the engine to overheat The use of modern high performance alcohol based model engine fuels while promoting cooler running improved anti detonatio...

Page 11: ... Head Screw N Round Head Screw S Set Screw C M3x12 C M3x16 C M2 6x8 C M2 6x8 F M2 6x6 2 30 2 3 3 1 3 2 4 4 1 4 2 5 5 4 5 3 5 2 5 1 6 7 8 9 1 10 11 12 13 14 15 17 18 19 20 21 22 30 1 30 2 23 24 25 26 6 1 6 2 6 3 6 4 28 29 C M3 5x20 16 24 27 30 31 32 34 33 C M2 6x18 18 1 18 2 18 3 ...

Page 12: ...10 11 12 13 14 15 16 17 44704200 44714300 45961400 45961410 45761600 44753000 44753100 45761200 44750000 44750100 45960210 45960310 45960400 44751000 44751100 45960210 45960310 45960400 44704100 44704000 45515000 44769400 44781000 44714100 29503400 44703200 45906000 44705000 44703100 18 18 1 18 2 18 3 19 20 21 22 23 24 25 26 27 28 29 30 30 1 30 2 31 32 33 34 44782000 44782160 45771000 22681957 447...

Page 13: ... 0mm 0 748in 2 000 15 000r p m 1 2ps 11 000r p m 455g 16 0oz JAPAN JAPAN 54 35 4 59 5 34 5 24 1 50 2 29 6 35 1 87 4 18 105 4 20 49 5 45 58 9 UNF1 4 28 4 3 7 92 26 7 45 20 39 5 142 25 6 without Locknut Drive Hub Woodruff Key F 4020 U Silencer Assembly 527 3g 18 61oz 51g 1 8oz With F 4020 U Silencer Assembly F 4020 U Silencer Assembly 24 MEMO ...

Page 14: ...ed Printed in Japan TEL 06 6702 0225 FAX 06 6704 2722 6 15 3 Chome Imagawa Higashisumiyoshi ku Osaka 546 0003 Japan 60091400 090304 URL http www os engines co jp U N E Q U A LLED QUALITY PRECISION PERFOR M A N C E E S T A BLISHING THE STANDARDS OF EXCELLE N C E ...

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