1/10 class for carMAX-12TG Ver.IV
It is of vital importance, before attempting to operate your engine, to read the general ‘SAFETY INSTRUCTIONS AND WARNINGS’ in the following section and to strictly adhere to the advice contained therein.
- Also, please study the entire contents of this instruction manual, so as to familiarize yourself with the controls and other features of the engine.
SAFETY INSTRUCTIONS AND WARNINGS ABOUT YOUR O.S. ENGINE
Remember that your engine is not a ” toy “, but a highly efficient internal-combustion machine whose power is capable of harming you, or others if it is misused or abused. As an owner, you, alone, are responsible for the safe operation of your engine, so act with discretion and care at all times. If at some future date, your O.S. engine is acquired by another person, we would respectfully request that these instructions are also passed on to its new owner. The advice which follows is grouped under two headings according to the degree of damage or the danger which might arise through misuse or neglect.
These cover events which might involve serious (in extreme circumstances, even fatal) injury.
These cover the many other possibilities, generally less obvious sources of danger, but which, under certain circumstances, may also cause damage or injury.
ENGINE CONSTRUCTION
With this engine, the piston will feel tight at the top of its stroke (TDC) when the engine is cold. This is normal. The cylinder bore has a slight taper. The piston and cylinder are designed to achieve a perfect running clearance when they reach operating temperature.
When the engine is cold. When the engine is hot.
NOTES WHEN APPLYING AN ELECTRIC STARTERDo not over-prime. This could cause a hydraulic lock and damage the engine on application of the electric starter. If over-primed, remove glowplug, close needle-valve, and apply starter to pump out surplus fuel. Cover the head with a rag to prevent any pumped-out fuel from getting into your eyes.
Model engine fuel is poisonous. Do not allow it to come into contact with the eyes or mouth. Always store it in a clearly marked container and out of the reach of children.
Model engine fuel is also highly flammable. Keep it away from open flame, excessive heat, sources of sparks, or anything else which might ignite it. Do not smoke or allow anyone else to smoke, near to it.
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.
Never operate your engine in an enclosed space. Model engines, like automobile engines, exhaust deadly carbon monoxide. Run your engine only in an open area.
- This engine is intended for model cars. Do not attempt to use it for any other purpose.
- Mount the engine in your model securely, following the manufacturers’ recommendations, using appropriate screws and locknuts.
While Operating
- Please do not run on a public street, this could cause serious accidents, personal injuries, and/or property damage.
- Please do not run near pedestrians or small children.
- Please do not run in small or confined areas.
- Please do not run where loud noises can disturb others, such as hospitals and residential areas.
NOTEAs delivered, the engine has the carburetor lightly fit into its intake. Secure it by changing its angle according to the car chassis.
- ABOUT THE PRODUCTMAX-12TG Ver.IV is a successor of MAX-12TG Ver. III. The new engine boasts the same connecting of OS SPEED T12 series, which is more durable and has racingspecifications. A crankcase and an outer head are newly designed. A refined piston enables smoother acceleration suitable for sports driving.
Standard accessories
- Glow Plug P4 T-type head (Turbo head) 1piece
- Exhaust Seal Ring 1piece
- Dust Cap 3mm, 16mm(2pcs.)
TOOLS, ACCESSORIES, etc.
The following items are necessary for operating the engine. Items necessary for startingFUELGenerally, it is suggested that the user selects a fuel that is commercially available for model two-stroke engines and contains 10-30% nitromethane. As a starting point, we recommend a fuel containing 20% nitromethane, changing to a fuel containing more nitro if necessary. When the brand of fuel is changed, or the nitro content increased, it is advisable to repeat the running-in procedure referred to in the RUNNING-IN paragraphs. Please note that with high-nitro fuels, although power may be increased for competition purposes, glowplug elements do not last as long and engine life will be shortened.
FUEL FILTERTo install in the fuel line between fuel tank and carburetor to prevent foreign matter from entering the carburetor.
GLOWPLUG IGNITERCommercial available handy glow plug heater in which the glowplug battery and battery leads are integrated.
STARTER BOXFor starting the engine.
FUEL PUMPFor filling the fuel tank, a simple, polyethylene “squeeze” bottle, with a suitable spout, is required.
SILICONE FUEL LINEHeatproof silicone tubing of approx. 5mm o.d. and 2mm i.d. is required for the connection between the fuel tank and engine.
| TOOLS | |
| O.S. SPEED PISTON PIN RETAINER PLIERS
O.S. SPEED DRIVER TOOLS |
|
| O.S. SPEED FLYWHEEL KEY | |
| O.S. SPEED
CLUTCH WRENCH & ADJUSTER |
|
| O.S. SPEED FLYWHEEL PULLER | |
| O.S. SPEED PLUG WRENCH |
BASIC ENGINE PARTS
CARBURETOR CONTROLS
Three adjustable controls are provided on this carburetor.
- The Needle-Valve (Adjusted at the factory):For adjusting the mixture strength when the throttle is fully open.
- The Metering Needle (Adjusted at the factory):For adjusting the mixture strength at part-throttle and idle speed, to obtain steady idling and smooth acceleration to mid-speed.
- The Throttle Stop Screw (Adjusted at the factory):For setting the minimum idle speed:NOTE: Readjustment may be necessary, occasionally to allow for changes in fuel formula, gear ratio, or clutch engagement point.
INSTALLATION OF THE CARBURETORAs delivered, the engine has its carburetor lightly installed in the intake boss. Secure it as follows.
- Loosen the retainer screw, rotate the carburetor to its correct position, and make sure that it is pressed well down into the intake boss, compressing the rubber gasket, before retightening the screw.
- Rotate the retainer screw gently until it stops, then tighten a further 60-90 . Do not overtighten the screw as this will damage the carburetor body.
ENGINE INSTALLATION
When installing the engine on the chassis, note the following points. (Chamfer inside edges of bearers when the engine mounts edges interfere with the engine. Do not chamfer the engine.)
Make sure that the vehicle’s engine mounting surfaces are level and in the same plane. Poor installation may cause distortion of the crankcase, bearings, etc., resulting in erratic running and loss of performance. The recommended screws for securing the engine are 3mm or 4-40 steel Allen hexagon socket type. If existing holes in the engine mount do not align perfectlywith engine mounting lugs, enlarge them slightly with a needle file so that screws are in alignment with the mounting holes.
STARTING THE ENGINE & RUNNING-IN (‘Breaking-in) RUNNING-IN (‘Breaking-in)Running-in is a procedure for an engine to come close to actual running conditions (fuel, r.p.m., engine temperature, etc.). Excessively rich running and prolonged low-speed running should be avoided. Prolonged low-speed running and low-temperature running may result in the oil in the fuel becoming gelled and the piston/liner becoming stuck together.PRESSURIZED FUEL SYSTEM
- The somewhat violent changes of vehicle attitude that occur in off-road running, combined with the fact that, in buggy type cars, the fuel tank is often located some distance from the carburetor, means that the fuel ‘head’ at the carburetor can vary and upset running. Therefore, it is recommended that a muffler pressurized fuel feed system be used.
- Never run your vehicle without installing the air cleaner. Dust and dirt that may otherwise be drawn into the engine will rapidly shorten its life.
The following procedure is suitable when a fuel containing 30% nitro-methane is used.
- Fill the tank completely with fuel.
- Temporarily remove the glowplug to check that it glows bright red when energized.The carburetor is set as shown below at the factory. Start the engine as it is.
- The needle-valve is set approx. 2.5 turns opened from the fully closed position.
Turn the needle valve clockwise until it stops. This is the fully closed position. Do not force it to turn further.
- Throttle is set approx. 0.5mm open.
REALIGNMENT OF METERING NEEDLEIn the course of making carburetor adjustments, it is just possible that the Metering Needle may be inadvertently screwed in or out too far and thereby moved beyond its effective adjustment range. The basic positions can be found by rotating the Metering Needle until its slotted head is flush with the ball link body.
- Switch on the transmitter and make sure that each linkage moves correctly.
- Turn the engine with the starter box to draw fuel into the engine.
- Now connect the glowplug battery lead to heat the plug filament and start the engine.When the engine does not start or stops right after being started, try the following.
- Set the needle-valve approx. 2 turns open from the fully closed position. Do not force the needle valve to turn beyond a lightly closed position.
- Set the throttle opening a little wider than the factory setting by adjusting the Throttle Stop Screw.
- When the engine starts, warm it up by repeatedly increasing the rpm to medium speed and back again to a fast idle with the mixture set very rich, the glowplug connected, and the driving wheels clear of the ground. The rich mixture will provide adequate lubrication and cooling indicated by profuse exhaust smoke.
Attention:It is vitally important to set the throttle at the correct position before starting the engine. If the engine is allowed to run with the throttle too far open under ”no-load” conditions (i.e. with the driving wheels not in contact with the ground) it will rapidly overheat and may be seriously damaged.
- Next, disconnect the glowplug battery and try running the car on the track. If the engine stalls, open the throttle fractionally but try to keep the engine running as rich as possible: if it stops because of being excessively over-rich, close the Needle-Valve 15˚ and try again.
- Run the car on the track until one tank of fuel has been consumed, then close the Needle-Valve 15˚ and run the car for 3 to 5 full tanks of fuel. Repeat this procedure until approx. 1 liter of fuel has been consumed, during which time the throttle may be opened for brief bursts of increased power. If the engine stops at medium speeds, close the Metering Needle 45˚.
Note:In the event of any major working parts (e.g. piston/cylinder liner assembly) being replaced or the fuel being changed, especially to high nitro fuel, the complete running-in should be repeated.
- How to stop the engineTo stop the engine, close the throttle to idle speed and shut it off completely with the trim lever on the transmitter then cut off the fuel supply by pinching the fuel delivery tube to the carburetor.
Warning!Do not touch rotating parts, engine, and silencer when stopping the engine as they become very hot, and contact with them may result in a serious burn.
FINAL ADJUSTMENTFinal adjustment should be carried out only after the running-in has been completed.
- Run the vehicle (with the throttle fully open) over the longest available straight course, in order to observe the model’s speed. Next return the car to the starting point, close the Needle-Valve 15˚ and repeat the run, taking note of the improvement in performance.
- Continue with further runs, gradually reducing the Needle-Valve setting and aiming to achieve the highest straight-line speed. Remember, however, that, if the Needle-Valve is shut down too far, the engine will overheat, and, accompanied by visibly diminished exhaust smoke, the model will lose speed. At this point, throttle down immediately, stop the vehicle and reopen the Needle-Valve 15˚.
- With the engine running, close the throttle and allow it to idle for about five seconds, then reopen the throttle fully. If, at this point, the engine puffs out an excessive amount of smoke and the vehicle does not accelerate smoothly and rapidly, it is probable that the idle mixture is too rich.
- In this case, turn the Metering Needle clockwise 15˚. If, on the other hand, the engine tends to speed up momentarily and then cut out abruptly when the throttle is opened, the idle mixture is too lean. Correct this by turning the Metering Needle counter-clockwise 15˚.
- Carry out adjustments patiently, under actualrunning conditions, until the engine respondsquickly and positively to the throttle control.
Warning!
Mixture adjustments (whether via the MeteringNeedle, or the Needle-Valve) cannot be made accurately under ‘no-load’ conditions, which, in any case, are not advised, since such operation carries the risk of seriously damaging the engine through over-revving and overheating.
- With the optimum mixture control position, light smoke is visible during high-speed running, and the engine rpm increases smoothly during acceleration. Remember that, if the engine is operated with the fuel/air mixture slightly too lean, it will overheat and run unevenly. As with all engines, it is advisable to set both the needle-valve and metering needle slightly on the rich side of the best rpm setting, as a safety measure.
- If the engine runs too fast with the throttle closed, the throttle stop screw should be turned counter-clockwise to allow the throttle opening to be reduced.
- Finally, beyond the nominal break-in period, a slight readjustment toward a leaner needle setting may be required to maintain maximum performance.
CARE AND MAINTENANCE
- The minute particles of foreign matter, that are present in any fuel may, by accumulating and partially obstructing fuel flow, cause engine performance to become erratic and unreliable.O.S. ‘Super-Filters’ (large and small) are available, as optional extras, to deal with this problem. One of these filters installed in the pickup tube inside your refueling container will prevent the entry of foreign material into the fuel tank. It is also recommended that a good in-line filter be installed between the tank and carburetor.
- Do not forget to clean the filters regularly to remove dirt and lint that accumulate on the filter screens. Also, clean the carburetor itself occasionally.
- At the end of each operating session, drain out any fuel that may remain in the fuel tank. Afterward, energize the glow-plug and try to restart the engine, to burn off any fuel that may remain inside the engine. Repeat this procedure until the engine fails to fire. Do this while the engine is still warm.
- Then, inject some after-run oil into the engine, and rotate the engine with an electric starter for 4 to 5 seconds to distribute the oil to all the working parts.Note: Do not inject after-run oil into the carburetor as this can cause the O rings inside the carburetor to deteriorate. Add the oil through the glowplug hole and turn the engine over several times by hand.
- Finally, when cleaning the exterior of the engine, use methanol or a household cleaning agent. Do not use gasoline, kerosene, or any petroleum-based chemical which can damage silicone fuel tubing.
CHECKING THE ENGINE
If the engine will not develop normal performance after a long time running due to the wearing of parts. It is suggested to replace necessary parts when the following symptoms are detected.
- Engine sound changes and easily overheats.
- Power has dropped extremely.
- Idle is unstable and/or engine tends to stop at idle.
In most cases, ball bearings, cylinder & piston assembly, connecting rod, and/or crankcase have become worn. Check the parts carefully and replace them if necessary.
- S. GENUINE PARTS & ACCESSORIES
- S. GLOW PLUG (T-type head)
- p3 (71641300) •P4(71641400) •P5(71641500)
- S. GLOW PLUG (Normal type head)
- 7 • No.8 • No.10 (Former A5)(71607100) (71608001) (71605100)
- FOR NORMAL PLUG INNER HEAD (21414120)
- 170211 EFRA2690 (T-1080SC L52) COMPLETE SET (72106980)
- TTO2 EFRA2690 (T-1080SC L52)
Tuned Silencer Assembly (72150010)
- Exhaust Seal Ring (2pcs.) (22826140)
- Joint Spring (3pcs.) (72106042)
- MT02(M1007SC) Exhaust Manifold ASSEMBLY
(72150020)
- Exhaust Manifold Spring (2pcs.) (72106172)
- Adapter Seal Ring (2pcs.) (21427200)
- 1701 EFRA2672 (T-1070SC L52) COMPLETE SET (72107600)
- 1701 EFRA2672 (T-1070SC L52) Tuned Silencer Assembly (72107610)
- Joint Spring (3pcs.) (72106042)
- Exhaust Seal Ring (2pcs.) (22826140)
- MT01(M1006SC) Exhaust Header Pipe Assembly (72107620)
- Header Pipe Spring (2pcs.) (72106172)
- Exhaust Seal Ring (2pcs.) (21427200)
- MT03 Exhaust Manifold ASSEMBLY
(72150020)
- Exhaust Manifold Spring (2pcs.) (72106172)
- Adapter Seal Ring (2pcs.) (21427200)
- SUPER AIR CLEANER 202 ASSEMBLY
(72412000) On-road Type
- 202 Cleaner Body (72412100)
- 202 Filter Element (4pcs.) (72412200)
- PRESSURE CHAMBER SET (71550000)
- INDUCTION SILENCER (72414000)
- Induction Silencer Filter (3pcs.) (72414100)
- ON-ROAD FILTER OIL (20m1) (72414200)
- S. SPEED CLUTCH BEARING (1050ZZ)
- (71550001) (4pcs.)
- (71550002) (10pcs.)
- S. SPEED CILICONE TUBE(72506100) 2 Omm I OCOrnm
- S. SPEED EXHAUST SEAL RING 12 (2N* ) (21427200)
- S. SPEED FLYWHEEL COLETE (2pcs.) (71931110)
- S. SPEED DUST CAP SET 3mm (73300305) (5pcs.)
- S. SPEED DUST CAP SET 16mm (73301612) (3pcs.)
- S. SPEED DUST CAP SET 18mm (73301812) (3pcs.)
- S. SPEED PISTON PIN RETAINER PLIERS (71492000)
- S. SPEED CLUTCH WRENCH & ADJUSTER (71415300)
- S. SPEED FLYWHEEL KEY (71415200)
- S. SPEED FLYWHEEL PULLER (71415100)
- S. SPEED PLUG WRENCH (71520100)
- S. SPEED SPRING REMOVER (71415500)
- S. SPEED BODY REAMER (71415400)
- S. SPEED PHILIPS SCREWDRIVER NO.1 (71417100)
- S. SPEED PHILIPS SCREWDRIVER No.2 (71417200)
- S. SPEED DRIVER TOOLS
| Code No. | Description |
| 71410150 | O.S. SPEED HEX WRENCH DRIVER 1.5 |
| 71410200 | O.S. SPEED HEX WRENCH DRIVER 2.0 |
| 71410250 | O.S. SPEED HEX WRENCH DRIVER 2.5 |
| 71410300 | O.S. SPEED HEX WRENCH DRIVER 3.0 |
| 71411200 | O.S. SPEED HEX BALL WRENCH DRIVER 2.0 |
| 71411250 | O.S. SPEED HEX BALL WRENCH DRIVER 2.5 |
| 71412300 | O.S. SPEED FLAT HEAD SCREWDRIVER 3.0 |
| 71413550 | O.S. SPEED NUT DRIVER 5.5 |
| 71413600 | O.S. SPEED NUT DRIVER 6.0 |
| 71413700 | O.S. SPEED NUT DRIVER 7.0 |
| Code No. | Description |
| 71414015 | O.S. SPEED HEX WRENCH TIP ONLY 1.5 |
| 71414020 | O.S. SPEED HEX WRENCH TIP ONLY 2.0 |
| 71414025 | O.S. SPEED HEX WRENCH TIP ONLY 2.5 |
| 71414030 | O.S. SPEED HEX WRENCH TIP ONLY 3.0 |
| 71414120 | O.S. SPEED HEX BALL WRENCH TIP ONLY 2.0 |
| 71414125 | O.S. SPEED HEX BALL WRENCH TIP ONLY 2.5 |
| 71414230 | O.S. SPEED FLAT HEAD SCREWDRIVER TIP 3.0 |
| 71414355 | O.S. SPEED NUT DRIVER TIP ONLY 5.5 |
| 71414360 | O.S. SPEED NUT DRIVER TIP ONLY 6.0 |
| 71414370 | O.S. SPEED NUT DRIVER TIP ONLY 7.0 |
The specifications are subject to alteration for improvement without notice.
THREE VIEW DRAWING
Dimensions (mm)
SPECIFICATIONS
| Displacement | 2.10 cc / 0.128 cu.in. |
| Bore | 13.8 mm / 0.543 in. |
| Stroke | 14.0 mm / 0.551 in. |
| Output | 0.9 ps / 0.88 hp / 30,000 r.p.m. |
| Practical R.P.M. | 5,000-32,000 r.p.m. |
| Weight | 216 g / 7.62 oz. (Engine) |
ENGINE PARTS LIST
| No. | Code No. | Description |
| 1 | 2D204000 | Outer Head |
| 2 | 21674100 | Inner Head |
| 3 | 2D203100 | Built-Up Parts Set |
| 3-1 | 2D203000 | Cylinder & Piston Assembly |
| 3-2 | 21656000 | Piston Pin |
| 3-3 | 2AP17000 | O.S.SPEED Piston Pin Retainer 2 (6pcs.) |
| 3-4 | 2A405001 | Connecting Rod w/piston pin retainers 2 (3pcs.) |
| 4 | 21418010 | Carburetor Complete (Type 12D2) |
| 5 | 25381701 | Carburetor Retainer Assembly |
| 5-1 | 23325340 | M3.5×0.60 Nut (2pcs.) |
| 6 | 21630500 | Crankshaft Ball Bearing (Front) |
| 7 | 2D201000 | Crankcase |
| 8 | 21931010 | Crankshaft Ball Bearing (Rear) |
| 9 | 21412000 | Crankshaft |
| 10 | 21411400 | Gasket Set |
| 11 | 21417000 | Cover Plate |
| 71641400 | Glow Plug T-P4 | |
| 21427210 | O.S. SPEED Exhaust Seal Ring 12 (10pcs.) | |
| 22884254 | O.S. SPEED Dust Cap Set For 12-30 Class 3mm (2pcs.)/16mm (2pcs.)/18mm (1pc) |
CAP SCREW SETS (10pcs./set)
| Code No. | Size | Pcs. used in an engine |
| 79871020 | M2.6×7 | Cover Plate Retaining Screw (4pcs.) |
| 79871150 | M3x15 | Cylinder Head Retaining Screw (4pcs.) |
CARBURETOR PARTS LIST
| No. | Code No. | Description |
| 1 | 21681900 | Needle Valve Assembly |
| 1-1 | 27881820 | “0” Ring (2pcs.) |
| 1-2 | 2AP81950 | No.21 Universal Nipple Assembly |
| 2 | 21982620 | Throttle Stop Screw |
| 2-1 | 22781800 | “0” Ring (S) (2pcs.) |
| 3 | 21418110 | Carburetor Body |
| 3-1 | 21982900 | Thermo Insulator |
| 4 | 21682200 | Slide Valve |
| 5 | 21538500 | Metering Needle Assembly |
| 5-1 | 22781800 | “0” Ring (S) (2pcs.) |
| 6 | 21982520 | Dust Cover |
| 7 | 23818430 | Ball Link No.5 |
| 7-1 | 26381501 | Set Screw |
| 8 | 22615000 | Carburetor Rubber Gasket |
MFG.CO., LTD.
http://www.os-engines.co.jp6-15 3-Chome Imagawa Higashisumiyoshi-kuOsaka 546-0003, Japan TEL. (06)6702-0225FAX. (06)6704-2722© Copyright 2020 by O.S. Engines Mfg. Co., Ltd. All rights reserved. Printed in JAPAN. 60093710 112001
References
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