BASIC ENGINE PARTS The Metering Needle: STARTING THE ENGINE & RUNNING-IN ('Breaking-in) For adjusting idle and acceleration feeling. Running- in is a procedure for an engine to come Outer Head W/12F5(B) close to actual running conditions (fuel, r.p.m., O.S. SPEED T1204 Ball Link engine temperature, etc.). [Standard Position] It is of vital importance, before attempting to operate your Install an effective silencer (). Frequent close Excessively rich running and prolonged low speed Flush with the Slide Valve body. running should be avoided. Prolonged low speed engine, to read the general 'SAFETY INSTRUCTIONS WARNINGS exposure to a noisy exhaust (especially in the case running and low temperature running may result AND WARNINGS' in the following section and to strictly fuel is poisonous. Do not of the more powerful highspeed engines) may eventually impair your hearing and such noise is Exhaust in the oil in the fuel becoming gelled and the adhere to the advice contained therein. allow it to come into contact with the eyes Metering Needle /liner becoming stuck together. or mouth. Always store it in a clearly marked also likely to cause annoyance to others over a wide Also, please study the entire contents of this Slide Valve container and out of the reach of children. area. PRESSURIZED FUEL SYSTEM instruction manual, so as to familiarize yourself with Carburetor Body the controls and other features of the engine. Model engine fuel is also highly flammable. The wearing of safety glasses is also strongly Cover Plate It is recommended that a muffler pressurized fuel feed system be used so that the fuel may be stably Keep it away from open flame, excessive recommended. The Stop Screw: fed to the carburetor. SAFETY INSTRUCTIONS AND WARNINGS ABOUT YOUR O.S. ENGINE heat, sources of sparks, or anything else Take care that the glowplug clip or battery leads do For setting the minimum idle speed: Remember that your engine is not a " toy ", but a which might ignite it. Do not smoke or allow not come into contact with rotating parts. Also check [Standard Position] The following procedure is suitable when a fuel highly efficient internal- machine whose anyone else to smoke, near to it. that the linkage to the throttle arm is secure. Approx 0.5mm containing 20% nitro-methane is used. power is capable of harming you, or others, if it is For their safety, keep all onlookers (especially small Mounting Lugs misused or abused. As owner, you, alone, are Model engines generate considerable 1. Set the carburetor controls at the standard positions heat. Do not touch any part of your engine children) well back (at least 20 feet or 6 meters) (positions when the engine leaves the factory.) responsible for the safe operation of your engine, so when preparing your model for running. Crankshaft Bearing (Front) act with discretion and care at all times. If at some until it has cooled. Contact with the 2. Switch the transmitter and make sure that each future date, your O.S. engine is acquired by another muffler (silencer), head or Before starting the engine, always check the linkage moves correctly. person, we would respectfully request that these exhaust header pipe, in particular, may tightness of all the screws and nuts especially those INSTALLATION OF THE STANDARD ACCESSORIES Carburetor Body instructions are also passed on to its new owner. result in a serious burn. of joint and movable parts such as throttle arm. Slide Valve 3. Make sure rotating direction of the box is Missing retightening the loose screws and nuts Installing the glow plug. Insert RP6 plug supplied into Note: correct (counter-clockwise seen from the front edge The advice which follows is grouped under two Never operate your engine in an enclosed space. often causes the parts breakage that is capable of heatsink-head carefully, making sure that it is not Sketch shows the carburetor reducer removed. of the crankshaft), and turn the engine with the headings according to the degree of damage or Model engines, like automobile engines, exhaust harming you. cross-threaded before tightening firmly. starter box to draw fuel into the engine. danger which might arise through misuse or neglect. deadly carbon-monoxide. Run your engine only in NOTE: While the Mixture Control Valve and the (All the O.S. T-Type plugs including the RP6 are not an open area. To stop the engine, fully retard the throttle stick and Metering Valve are set at the standard position 4. Connect glowplug battery lead to heat the plug and WARNINGS trim lever on the trans-mitter, or, in an emergency, supplied with a washer.) when the engine leaves the factory, readjustment start the engine with the starter box. cut off the fuel supply by pinching the fuel delivery may be necessary, occasionally to allow for When the engine does not start or stops right after These cover events which might involve serious NOTES line from the tank. Install the exhaust seal ring changes in fuel formula and climatic conditions being started, try the followings. (in extreme circumstances, even fatal) injury. This engine is intended for model . Do not Readjust the controls only when satisfactory Warning! Immediately after a glowplug-ignition engine supplied. Set the needle-valve approx. 2 turns open from the attempt to use it for any other purpose. results cannot be obtained with the standard has been run and is still warm, conditions sometimes NOTES positions following the instructions mentioned in fully closed position. Do not force the needlevalve to Mount the engine in your model securely, following exist whereby it is just possible for the engine to abruptly the “CARBURETOR ADJUSTMENT” section. turn beyond a lightly closed position. These cover the many other possibilities, generally less the manufacturers' recommendations, using restart if it is rotated over compression WITHOUT the obvious sources of danger, but which, under certain Exhaust Set the throttle opening a little approx 1mm appropriate screws and locknuts. glowplug battery being reconnected. INSTALLATION OF THE CARBURETOR circumstances, may also cause damage or injury. Seal Ring wider (approx. 1mm) than the As delivered, the engine has its carburetor lightly installed standard setting by adjusting NOTES ON OPERATION TOOLS, ACCESSORIES, etc. in the boss. Secure it as follows. the Throttle Stop Screw. ENGINE CONSTRUCTION The following items are necessary for operating the engine. CARBURETOR CONTROLS STANDARD POSITIONS Rotate the retainer screw With this engine, the piston will feel tight at the ABOUT THE WARRANTY Items necessary for starting (POSITIONS WHEN THE ENGINE LEAVES THE FACTORY) gently until it stops. Since this is a special SPEED version, individual top of its (TDC) when the engine is cold. FUEL Four adjustable controls are provided on this 5. When the engine starts, warm it up by repeatedly This is normal. The cylinder has a slight special parts are available only for limited period Generally, it is suggested that the user selects a fuel that is carburetor. Tighten a further increasing the rpm to medium speed and back taper. The piston and cylinder are designed to (one year after finishing the production). commercially available for model two-stroke engines When Carburetor Reducer 120-180 again to a fast idle with the mixture set very rich, achieve a perfect running clearance when they Also, the engine is free of warranty due to damage the brand of fuel is changed, or the nitro content increased, it glowplug connected, and the driving wheels clear of reach operating temperature. and/or wear occurred during running. is advisable to repeat the running-in procedure referred to in Dust Cover the ground. The rich mixture will provide adequate the RUNNING-IN paragraphs. Please note Needle Valve Pull out lubrication and cooling, indicated by profuse Near TDC While Operating that with high-nitro fuels, although power exhaust smoke. Please do not run on a public street, this could may be increased for competition purposes, Attention: cause serious accidents, personal injuries glowplug elements do not last as long and Retaining It is vitally important to set the and/or propetry damage. engine life will be shortened. Screw "O" Ring throttle at the correct position Please do not run near pedestrians or small Ball Link before starting the engine. If Piston Cylinder children. To installed in the fuel line between fuel Throttle Stop Metering Needle the engine is allowed to run with the throttle too far open Liner Please do not run in small or confined areas. tank and carburetor to prevent foreign Screw Mixture Control Valve matter from entering the carburetor. Themo Insulator under ''no load'' conditions Please do not run where loud noises can disturb (i.e. with the driving wheels not in contact with the Crankshaft others, such as hospitals and residential areas. GLOWPLUG IGNITER "O" Ring ground) it will rapidly over-heat and may be Commercialy available handy glowplug The Needle-Valve: seriously damaged. Slight taper heater in which the glowplug battery and For adjusting air/fuel ratio (air-fuel mixture) at maximum 1. Loosen the retainer screw, rotate the carburetor to its NOTE 6. When the engine is warmed up, disconnect the battery leads are integrated. rpm (fully opened throttle). correct position and make sure that it is pressed well glowplug battery and try running the on the As delivered, the engine has the carburetor down into the intake boss, compressing the rubber STARTER BOX track. If the engine stops soon after running at lightly fit into its intake. Secure it changing its , before retightening screw. angle according to the car chassis. For starting the engine. Close(Clockwise) around mid speed, the mixture is too rich. Close the Needle Valve 2. Rotate the retaining screw gently until it stops, then needle-valve 15°. tighten a further 120-180 , and no more. If the engine still stalls, close the metering needle 15°. Run the car on the track until one tank of fuel ABOUT THE ENGINE For filling the , a simple, polyethylene Do not overtighten the screw as this will damage the When the engine is cold. When the engine is hot. "squeeze" bottle, with a suitable spout, is required. has been consumed, then close the needle-valve Open thermo insulator. O.S. SPEED T1204 is designed to clear the IFMAR very little (within 10°). O.S. SPEED SILICONE FUEL LINE (optional extra) (Counter-clockwise) Note regulations for 1/10 touring car category. Be careful not to damage the O rings when The connection between the fuel tank and the engine. 7. Repeat this procedure (close needle-valve very little The new crankshaft has two weights made of removing the carburetor retainer from the engine. 2.5mm ID after one tank of fuel has been consumed) until approx. NOTES WHEN APPLYING AN ELECTRIC STARTER tungsten in the counterweight to improve torque in [Standard Position] First, remove the Retaining screw, then pull out 2 liters of fuel have been consumed, extending gradually middle range. 2.5 turns opened from the fully closed position. each retainer. Do not push the retainers in or the O the full throttle running time at the straight. Carefully Do not over-prime. This could cause a TOOLS (optional extra) The inner head is sealed by an o-ring to prevent rings will get damage. observe the exhaust smoke. hydraulic lock and damage the engine on [Fully closed position] application of the electric starter. dust from going into the . O.S. SPEED PISTON PIN RETAINER PLIERS Be sure to run the engine with visible white smoke at Turn the needle-valve clockwise until it stops. ENGINE INSTALLATION all times. If the smoke is not visible, the needle-valve If over-primed, remove glowplug, close Fin pitch of the outer head is widened for better O.S. SPEED DRIVER TOOLS This is the fully closed position. Make sure that the vehicle's engine mounting surfaces needle-valve and apply starter to pump out cooling. is closed too far. surplus fuel. Cover the head with a rag to Do not force it to turn further. are level and in the same plane. Poor installation may Now the RUNNING-IN (Breaking-in) is completed. cause distortion of the crankcase, bearings, etc., prevent any pumped out fuel from getting into Note: resulting in erratic running and loss of performance. your eyes. Standard accessories In the event of any major working parts (e.g. The recommended screws for securing the engine are piston/cylinder liner assembly) being replaced or The Mixture Control Valve: 3mm or 4-40 steel Allen hexagon socket type. If existing the fuel being changed, especially to high nitro For adjusting acceleration feeling. holes in the engine mount do not align perfectly with Glow Plug RP6 fuel, the complete running-in should be repeated. T-type head (Turbo head) 1piece (Adjusting range should be within ±1 turn.) engine mounting lugs, enlarge them slightly with a needle-file so that screws are in alignment with the How to stop the engine mounting holes. [Standard Position] To stop the engine, close the throttle to idle speed and shut it off Flush with the carburetor body. Exhaust Seal Ring 1piece O.S. SPEED KEY completely with the trim lever on the transmitter then cut off the fuel O.S. SPEED Do not allow bottom supply by pinching the fuel delivery Dust Cap Set of crankcase to tube to the carburetor. 3mm 1piece 16mm 2pcs. CLUTCH WRENCH & ADJUSTER Mixture Control Valve touch chassis. Warning! Carburetor Body O.S. SPEED FLYWHEEL PULLER Do not touch rotating parts, engine and silencer when stopping the Fuel O.S. SPEED PLUG WRENCH engine as they become very hot, Chamfer inside edges of bearers. and contact with them may result in a serious burn. FINAL ADJUSTMENT 3. At the end of each operating session, drain out any fuel SUPER AIR CLEANER 202 ASSEMBLY ENGINE EXPLODED VIEW ENGINE PARTS LIST that may remain in the fuel tank. Afterwards,energize On-road Type (72412000) Final adjustment should be carried out only after the Type of screw the glow-plug and try to restart the engine, to burn off 202 Cleaner Body C.M3x15 No. Code No. Description running-in has been completed. C...Cap Screw any fuel that may remain inside the engine. Repeat this (72412100) 1 2CS04000 Outer Head procedure until the engine fails to fire. Do this while the 202 Filter Element (4pcs.) 2 2CS04100 Inner Head engine is still warm. (72412200) Needle Valve Metering Needle 2-1 2CS04180 Inner Head "O" Ring 4. Then, inject some after-run oil into the engine, and PRESSURE CHAMBER SET 1 3 Set (0.1mm, 0.15mm) rotate the engine with an electric starter for 4 to 5 2A404160 Open Close Open Close (71550000) seconds to distribute the oil to all the working parts. 4 2CS03010 Built-Up Parts Set Note: INDUCTION SILENCER 4-1 2BS03000 Cylinder & Piston Assembly (72414000) Do not inject after-run oil into the carburetor as 4-2 21656000 Piston Pin Induction Silencer Filter (3pcs.) this may cause the O-rings inside the carburetor to 4-3 2AP17000 O.S.SPEED Piston Pin Retainer 2 (6pcs.) More fuel Less fuel More fuel Less fuel (72414100) 2 deteriorate. These procedures will reduce the risks 4-4 2A405001 (w/piston pin retainers 2 3pcs.) ON-ROAD FILTER OIL (20ml) 2-1 of starting difficulties or corrosion after a period of 5 2BS81000 Carburetor Complete (Type 12F5(B)) storage. (72414200) 1. NEEDLE VALVE ADJUSTMENT 6 21538170 Carburetor Retainer Assembly 5. Finally, when cleaning the exterior of the engine, use O.S. SPEED CLUTCH BEARING (1050ZZ 4pcs.) 3 6-1 24881824 "O" Ring (2pcs.) Run the vehicle (with throttle fully open) over the methanol or a household cleaning agent. Do not use (71550001) longest available straight course a few times to gasoline, kerosene, or any petroleum based 7 21630500 Ball Bearing (F) O.S. SPEED CLUTCH BEARING (1050ZZ 10pcs.) 4 observe the model’s speed. Return the vehicle to the chemical which can damage silicone fuel tubing. 8 2CS01000 Crankcase starting point and close the Needle-valve 15°and (71550002) 9 21931100 Ceramic Bearing (R) repeat the run, taking note of the improvement in 4-1 Note: O.S. SPEED CILICONE TUBE 10 2CS02000 Crankshaft performance. 4-3 Crankshaft of this engine is filled with silicone. (72506100) ID. 2.5mm x Length 1000mm "O" Ring (1pc.) Continue with further runs, gradually reduce the 4-3 11 21921800 Needle-valve setting aiming to achieve the highest Do not use light oil nor kerosene, etc. for O.S. SPEED EXHAUST SEAL RING 12 (10pcs.) 12 2BS07000 Cover Plate straight-line speed (optimum position). washing, or the silicone will swell. Use alcohol (21427210) 4-2 71642060 Glow Plug RP6 Remember, however, if the Needle-valve is closed too or fuel for washing and dry it completely. 5 4-4 C.M2.6x7 (2pcs.) 21427200 Exhaust Seal Ring (2pcs.) far, the engine will overheat, accompanied by visibly O.S. SPEED FLYWHEEL COLETTE 12 (71801110) Dust Cap Set (3mmx1,16mmx2) diminished exhaust smoke and the model will lose C.M2.6x15 11 21682950 speed. At this point, throttle down immediately, stop DUST CAP SET 3mm (5pcs.) Items marked * are available for only limited time. the vehicle and reopen the Needle-valve 15°. 10 Dirt and dust may lodge in marked places. (73300305) (One year after discontinuing the production) 2. METERING NEEDLE ADJUSTMENT CAP SCREW SETS (10pcs./set) DUST CAP SET 16mm (3pcs.) Code No. Size Pcs. used in an engine After setting the Needle-valve at optimum position, (73301612) 6 7 9 79871020 M2.6x7 Cover Plate Retaining Screw (4pcs.) run the vehicle a few times at the straightway, and M2.6x15 Carburetor Retainer Retaining Screw (1pc.) stop the vehicle. With the engine still running, close DUST CAP SET 12-30 (3mmx2,16mmx2,18mmx1) 79871050 79871150 M3x15 Retaining Screw (4pcs.) the throttle and allow it idle for about five seconds, (22884254) 8 6-1 then reopen the throttle fully. If, at this point, the engine puffs out an excessive O.S. SPEED PISTON PIN RETAINER PLIERS (71492000) CARBURETOR EXPLODED VIEW CARBURETOR PARTS LIST amount of smoke and the vehicle does not accelerate smoothly and rapidly or even stops, it is O.S. SPEED CLUTCH WRENCH & ADJUSTER Type of screw No. Code No. Description probable that the idle mixture is too rich. In this (71415300) S...Set Screw 1 21682600 Mixture Control Valve Assembly case, turn the Metering needle clockwise 15°. 1-1 27881820 "O" Ring (L) (2pcs.) If, on the other hand, the engine tends to speed up O.S. SPEED FLYWHEEL KEY momentarily with little smoke and then cut out REMOVING DIRT/STAIN (71415200) 2-1 1-2 22781800 "O" Ring (S) (2pcs.) abruptly when the throttle is opened, the idle Dirt and stain stuck on the engine and silencer/manifold 2-2 2 2AP11000 Needle Valve Assembly O.S. SPEED FLYWHEEL PULLER mixture is too lean. In this case, turn the Metering cause lowering heat dissipation effect. When dirt and 2-1 21538900 Needle (71415100) 2 needle counter-clockwise 15°. stain are detected, remove the engine from the chassis 3-1 3 2-2 27881820 "O" Ring (2pcs.) and clean it with alcohol. O.S. SPEED PLUG WRENCH 3. THROTTLE STOP SCREW ADJUSTMENT 2-3 21682940 Needle Hoolder (71520100) 3-1 If the engine runs too fast with the throttle closed, the INATALLING DUST CAPS 2-3 2-4 2AP81950 No.21 Universal Nipple Assembly throttle stop screw should be turned counter-clockwise When storing the engine, install the cap on the exhaust O.S. SPEED SPRING REMOVER 2-4 3 71533455 Carburetor Reducer (5.5mm Red) AL2 to allow the throttle opening to be reduced. 4 port, carburetor, etc. to prevent dust from entering the (71415500) 3-1 22615000 "O" Ring (1pc.) OPTIMUM MIXTURE CONTROL POSITION engine. O.S. SPEED BODY REAMER 4-1 4 21982620 Throttle Stop Screw With the optimum mixture control position, light smoke CHECKING THE ENGINE (71415400) 4-1 22781800 "O" Ring (S) (2pcs.) is visible during high speed running and the engine rpm O.S. SPEED PHILLIPS SCREW DRIVER 1-1 5 2BS81100 Carburetor Body (w/Thermo Insulator) increase smoothly during acceleration. Carry out If the engine will not develop normal performance after 1-2 6 7 adjustment 1.~3. patiently until the engine responds long time running due to wearing of parts. It is suggested No.1 (71417100) 5-1 21982900 Thermo Insulator to replace necessary parts when the following symptoms quickly and positively to the throttle control. O.S. SPEED PHILLIPS SCREW DRIVER 6 2A481200 Slide Valve are detected. 1 7-1 Remember that, if the engine is operated with the fuel/air No.2 (71417200) 5 7 21682510 Metering Needle Assembly mixture slightly too lean, it will overheat and run Engine sound changes and easily overheats. 8 9 7-1 22781800 "O" Ring (S) (2pcs.) unevenly. As with all engines, it is advisable to set both O.S. SPEED DRIVER TOOLS 5-1 Power has dropped extremely. 8 21982520 Dust Cover the needle-valve and metering needle slightly on the rich Code No. Description 9-1 Idle is unstable and/or engine tends to stop at idle. 9 23818430 Ball Link No.5 side of the best rpm setting, as a safety measure. 71410150 O.S. SPEED HEX WRENCH DRIVER 1.5 10 Finally, beyond the normal break-in period, a slight In most cases, ball bearings, cylinder & piston assembly, 71410200 O.S. SPEED HEX WRENCH DRIVER 2.0 9-1 26381501 Set Screw readjustment toward a leaner needle setting may be S.M3x3 connecting rod and/or crankcase have become worn. 71410250 O.S. SPEED HEX WRENCH DRIVER 2.5 10 22615000 Carburetor Rubber Gasket required to maintain maximum performance. Check the parts carefully and replace them if necessary. 71410300 O.S. SPEED HEX WRENCH DRIVER 3.0 Note: 71411200 O.S. SPEED HEX BALL WRENCH DRIVER 2.0 Please regard the standard positions in the O.S. GENUINE PARTS & ACCESSORIES 71411250 O.S. SPEED HEX BALL WRENCH DRIVER 2.5 THREE VIEW DRAWING Dimensions (mm) instruction manual as just a guide. Positions will O.S. GLOW PLUG 71412300 O.S. SPEED FLAT HEAD SCREWDRIVER 3.0 vary due to the fuel and silencer used. In general, SPECIFICATIONS RP6 (71642060) RP7 (71642070) 71413550 O.S. SPEED NUT DRIVER 5.5 if a fuel containing less nitromenthane is used, the 71413600 O.S. SPEED NUT DRIVER 6.0 Displacement 2.10 cc / 0.128 cu.in. needlevalve will need to be closed further. TT01 EFRA2672 (T-1070SC L52) 71413700 O.S. SPEED NUT DRIVER 7.0 Bore 13.67 mm / 0.538 in. Remember, closing the needlevalve too far can Stroke TUNED SILENCER COMPLETE SET 14.3 mm / 0.563 in. 31.4 cause rusting and damage to the engine. (72107600) Output 1.75 ps / 1.73 hp / 35,000 r.p.m. Code No. Description Practical R.P.M. 5,000-45,000 r.p.m. TT01 EFRA2672 (T-1070SC L52) 71414015 O.S. SPEED HEX WRENCH TIP ONLY 1.5 Weight 233 g / 8.22 oz. (Engine) CARE AND MAINTENANCE Tuned Silencer Assembly (72107610) 71414020 O.S. SPEED HEX WRENCH TIP ONLY 2.0 11 4- 3.3 1. The minute particles of foreign matter, that are present in Joint Spring (3pcs.) 71414025 O.S. SPEED HEX WRENCH TIP ONLY 2.5 any fuel may, by accumulating and partially obstructing (72106042) 71414030 O.S. SPEED HEX WRENCH TIP ONLY 3.0 fuel flow, cause engine performance to become erratic Exhaust Seal Ring (2pcs.) 71414120 O.S. SPEED HEX BALL WRENCH TIP ONLY 2.0 and unreliable. (22826140) O.S. SPEED HEX BALL WRENCH TIP ONLY 2.5 O.S. 'Super-Filters' (large and small) are available, as 71414125 MT01(M1006SC) Exhaust Header Pipe Assembly optional extras, to deal with this problem. 71414230 O.S. SPEED FLAT HEAD SCREWDRIVER TIP 3.0 (72107620) One of these filters installed to the pickup tube inside 71414355 O.S. SPEED NUT DRIVER TIP ONLY 5.5

Header Pipe Spring (2pcs.) 68.05 your refueling container, will prevent the entry of foreign (72106172) 71414360 O.S. SPEED NUT DRIVER TIP ONLY 6.0 material into the fuel tank. It is also recommended that a 71414370 O.S. SPEED NUT DRIVER TIP ONLY 7.0 Exhaust Seal Ring (2pcs.) UNF1/4-28 good in-line filter be installed between the tank and (21427200) carburetor. 23.5 MT03 EXHAUST HEADER POPE ASSEMBLY 2. Do not forget to clean the filters regularly to remove (72106550) dirt and lint that accumulate on the filter screens. Header Pipe Spring (2pcs.) 13.5 Also, clean the carburetor itself occasionally. (72106172) 26 29.5 50.0 6-15 3-Chome Imagawa Higashisumiyoshi-ku Exhaust Seal Ring (2pcs.) 39 Osaka 546-0003, Japan TEL. (06)6702-0225 (21427200) http://www.os-engines.co.jp FAX. (06)6704-2722

The specifications are subject to alteration for improvement without notice. Copyright 2020 by O.S. Engines Mfg. Co., Ltd. All rights reserved. Printed in JAPAN. 60093700 102000