It is of vital importance, before attempting to operate your engine, to read the general 'SAFETY INSTRUCTIONS AND WARNINGS' section on pages 2-5 of this booklet 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. Keep these instructions in a safe place so that you may readily refer to them whenever necessary.
SAFETY INSTRUCTIONS AND WARNINGS ABOUT YOUR O.S. ENGINE Remember that your engine is not a "toy", but a highly efficient internalcombustion machine whose power is capable of harming you, or others, if it is misused. As 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.
! NOTES This engine is intended for model cars. Do not attempt to use it for any other purpose. Take care that the glowplug clip or battery leads do not come into contact with rotating parts. Also check that the linkage to the throttle arm is secure. Mount the engine in your model securely, following the manufacturer's recommendations, using appropriate screws and locknuts.
ENGINE CONSTRUCTION Near TDC 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. Piston Cylinder Liner Crankshaft Slight taper When the engine is cold. When the engine is hot. 6 Notes when starting the engine Do not over-prime.
MAX-21VG The 21VG Series engines are developed for 1/8 scale R/C cars. They are rear exhaust engines designed for sport use. For easier handling newly designed 21F carburetor these engines are equipped with a and also a No.8 glowplug is supplied. They have mild and smooth accelerating characteristics which are most suitable for sport runs. Recoil starter incorporated versions which eliminate the need for a separate electric starter and starter battery are also available.
TOOLS, ACCESSORIES, etc. REMINDER! 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. The following items are necessary for operating the engine. ! Items necessary for starting FUEL Generally, it is suggested that the user selects a fuel that is commercially available for model two-stroke engines and contains 10-30% nitromethane.
INSTALLING THE GLOWPLUG Standard accessories MAX-21VG-P, MAX-21VG-PX, MAX-21VG-P Fit washer to glowplug and insert carefully into cylinder-head, making sure that it is not cross-threaded before tightening firmly. ES Glow Plug No.8 1piece Exhaust Seal Ring 1piece Socket Wrench Install the exhaust seal ring supplied. Glowplug Washer Exhaust Seal Ring 12 CARBURETOR CONTROLS Three adjustable controls are provided on this carburetor.
2. Rotate the retainer screw gently until it stops, then INSTALLATION OF THE CARBURETOR tighten a further 60-90˚. Do not overtighten the screw as this will damage the carburetor body. NOTE As delivered, the engine has its carburetor lightly fit into its intake. Secure it changing its angle according to the car chassis. When changing the ball link direction, loosen the retaining screw with a 1.5mm Hex wrench. Ball Link As delivered, the engine has its carburetor lightly fit into the intake boss.
GLOWPLUG Glowplug life Since the glowplug and fuel combination used may have a marked effect on performance and reliability, it would be worthwhile to experiment with different plug types. An O.S. No.8 glowplug is supplied with the engine. Recommended O.S. plugs are the No.8 and A5. Carefully install plug finger-tight, before final tightening with the correct size plug wrench. Particularly in the case of very high performance engines, glowplugs must be regarded as expendable items.
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.). While Operating Please do not run on a public street, this could cause serious accidents, personal injuries and/or propetry damage. Excessively rich running and prolonged low speed running should be avoided.
The carburetor is set as shown below at the factory. Start the engine as it is. Approx. 0.5mm open factory setting The needle-valve is set approx. 3 turns open from the fully closed position. approx 0.5mm Turn the needle-valve clockwise until it stops. This is the fully closed position. Do not force it to turn further. Metering needle is set at basic position. (Refer to P28.) Close (clockwise) Note Check the throttle opening at idle before installing an air cleaner.
In case of the 21VG-P Now connect glowplug battery lead to heat the plug filament and start the engine. Start the engine using a starter box, making sure the engine rotation direction is correct (counterclockwise seen from the crankshaft end). In case of the 21VG-PX Be sure to install an air cleaner when starting. In case of the 21VG-P ES Pull the starter handle briskly straight out several times to start the engine. Use the ROTO START to start the engine.
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 30˚ and try again. 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.
Adjust medium and low RPM running. Carry out adjustments patiently, under actual running conditions, until the engine responds quickly and positively to the throttle control. 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.
REALIGNMENT OF METERING NEEDLE In the course of making carburetor adjustments, it is just possible that the Metering Needle and the Mixture Control Screw 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.
Engine fires intermittently but does not run. Corrective action Cause Insufficient fuel in the tank. Fill the tank with fuel. Deteriorated glowplug Replace glowplug. Clogged fuel filter Air cleaner and silencer inside is dirty. Clean or replace fuel filter. Replace cleaner element and clean inside silencer. Engine overheated Wait until engine cools. Incorrect clutch release Adjust the tension of clutch spring. Glowplug battery disconnected too soon.
Poor response Corrective action Cause Deteriorated glowplug Replace glowplug. Incorrect carburetor settings Readjust low r.p.m. range with metering needle or mixture control screw. Incorrect setting of transmitter Exponential function. Check the transmitter setting. Make sure the throttle servo linkage does not bind and is connected correctly. Incorrect linkage Poor r.p.m. drop Corrective action Cause Throttle position open too far.
Then, inject some after-run oil into the engine, and rotate the engine with an electric starter or the recoil 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 may cause the O-rings inside the carburetor to deteriorate. These procedures will reduce the risks of starting difficulties or corrosion after a period of storage. Finally, when cleaning the exterior of the engine, use methanol.
37 1 2 3 4 5 6 7 8 9 10 11 12 12-1 13 14 Description Heatsink Head Cylinder & Piston Assembly Piston Pin Piston Pin Retainer (2pcs.) Connecting Rod Carburetor Complete (Type 21F) Carburetor Retainer Assembly Crankshaft Ball Bearing (Front) Crankcase Crankshaft Ball Bearing (Rear) Crankshaft Gasket Set Cover Gasket Cover Plate Screw Set Glow Plug No.8 Exhaust Seal Ring The specifications are subject to alteration for improvement without notice. Code No.
39 1 2 3 4 5 6 7 8 9 10 11 12 12-1 13 14 15 15-1 15-2 16 Description Heatsink Head Cylinder & Piston Assembly Piston Pin Piston Pin Retainer (2pcs.) Connecting Rod Carburetor Complete (Type 21F) Carburetor Retainer Assembly Crankshaft Ball Bearing (Front) Crankcase Crankshaft Ball Bearing (Rear) Crankshaft Gasket Set Cover Gasket Starting Shaft Rear Adaptor No.N3 Recoil Starter Assembly No.N3 Recoil Starter Body One-way Clutch Screw Set Glow Plug No.
41 1 2 3 4 5 6 7 8 9 10 11 12 12-1 13 14 15 16 17 Description Heatsink Head Cylinder & Piston Assembly Piston Pin Piston Pin Retainer (2pcs.) Connecting Rod Carburetor Complete (Type 21F) Carburetor Retainer Assembly Crankshaft Ball Bearing (Front) Crankcase Crankshaft Ball Bearing (Rear) Crankshaft Gasket Set Cover Gasket Starting Shaft (For Roto Start) Rear Adaptor (For Roto Start) One-way Clutch ES Starter Assembly Screw Set Glow Plug No.
21F CARBURETOR EXPLODED VIEW 2-1 2-2 2 2-3 2-4 1-1 1 5 4 5-1 3 6 8 7 Type of screw S.M3x3 C...Cap Screw M...Oval Fillister-Head Screw F...Flat Head Screw N...Round Head Screw S...Set Screw 42 21F CARBURETOR PART LIST No. Code No. 1 1-1 2 2-1 2-2 2-3 2-4 3 4 5 5-1 6 7 8 22848160 27881820 23618190 23618197 46066319 23619194 23818176 23618130 23981210 23981510 27881820 23981520 23781400 29015019 Description Mixture Control Screw "O" Ring (2pcs.
O.S. Glow Plug No.8 M2000SC Exhaust Header Pipe Assembly M2000 Exhaust Header Pipe Assembly (72106440) (72106430) (71608001) A5 (71605100) (72101272) (72101272) Exhaust Seal Ring (2pcs.) Exhaust Seal Ring (2pcs.) (22826140) (22826140) (72106130) Exhaust Seal Ring (2pcs.) (22826140) Joint Spring (3pcs.) (72106042) (72106090) Header Pipe Spring (2pcs.) Header Pipe Spring (2pcs.
21VG-P THREE VIEW DRAWING 54 SPECIFICATIONS 3.46 cc (0.211 cu.in.) 16.6 mm (0.654 in.) 16.0 mm (0.63 in.) 3,000-36,000 r.p.m. 2.0 ps / 30,000 r.p.m. 347 g (12.24 oz.) 37 ■ Displacement ■ Bore ■ Stroke ■ Practical R.P.M. ■ Power output ■ Weight 4- 3.3 87.4 21 UNF1/4-28 30.8 45 29.5 21.6 44 Dimensions (mm) 46 21VG-PX THREE VIEW DRAWING SPECIFICATIONS 37 54 3.46 cc (0.211 cu.in.) 16.6 mm (0.654 in.) 16.0 mm (0.63 in.) 3,000-36,000 r.p.m. 2.0 ps / 30,000 r.p.m. 395 g (13.93 oz.) 4- 3.
54 21VG-P ES THREE VIEW DRAWING SPECIFICATIONS 3.46 cc (0.211 cu.in.) 16.6 mm (0.654 in.) 16.0 mm (0.63 in.) 3,000-36,000 r.p.m. 2.0 ps / 30,000 r.p.m. 433 g (15.27 oz.) 37 ■ Displacement ■ Bore ■ Stroke ■ Practical R.P.M. ■ Power output ■ Weight 4- 3.3 87.4 21 UNF1/4-28 30.8 45 29.5 44 21.3 14.3 Dimensions (mm) 48 URL : http://www.os-engines.co.jp 6-15 3-Chome Imagawa Higashisumiyoshi-ku Osaka 546-0003, Japan TEL. (06) 6702-0225 FAX. (06) 6704-2722 C Copyright 2006 by O.S.Engines Mfg. Co.
