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.
WARNINGS • 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. • 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 engines generate considerable heat. Do not touch any part of your engine until it has cooled.
NOTES • This engine is intended for model cars. Do not attempt to use it for any other purpose. • The wearing of safety glasses is also strongly recommended. • Mount the engine in your model securely, following the manufacturers' recommendations, using appropriate screws and locknuts. • 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. • Install an effective silencer (muffler).
NOTES • To stop the engine, fully retard the throttle stick and trim lever on the trans-mitter, or, in an emergency, cut off the fuel supply by pinching the fuel delivery line from the tank. • Warning! Immediately after a glowplugignition engine has been run and is still warm, conditions sometimes exist whereby it is just possible for the engine to abruptly restart if it is rotated over compression WITHOUT the glowplug battery being reconnected.
The MAX-21VZ-R is high performance 3.5cc class power unit for one-eighth-scale radiocontrolled 'Track racing' cars. It has been designed to meet the exacting requirements of the world's most expert drivers. An exhaustive program of research, development and prototype testing has resulted in one of the most powerful production model racing car engines currently available. BASIC ENGINE PARTS Heatsink Head Carburetor Type 20K Exhaust Cover Plate Standard accessories Glow Plug P7 Cylinder-head gasket (0.
1. Insert carefully into heatsink head, making sure that it is not cross-threaded before tightening firmly. ENGINE INSTALLATION 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.
• Install a plug suitable for the engine. • Use fuel containing a moderate percentage GLOWPLUG of nitromethane unless more is essential for racing events. Since the compatibility of glowplug and fuel may have a marked effect on performance and reliability, it may be worthwhile to choose the R/C type plug found most suitable after tests. Recommended O.S. plugs are P7. Carefully install plug finger-tight, before final tightening with the correct size plug wrench.
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. TOOLS, ACCESSORIES, etc. The following items are necessary for operating the engine. 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.
• The Metering Needle: LONG SOCKET WRENCH Recommended for easy removal and replacement of the angled and recessed glowplug, the O.S.Long Socket Wrench incorporates a special grip. For adjusting the mixture strength at part-throttle and idling speeds, to obtain steady idling and smooth acceleration to mid speeds. • The Throttle Stop Screw: For setting the minimum idling speed: SILICONE FUEL LINE Needle Valve Heatproof silicone tubing of approx. 5mm o.d. and 2mm i.d.
STARTING THE ENGINE & RUNNING-IN ('Breaking-in') For long life and high performance, every engine needs to be 'run-in' or 'broken-in'. With care, runningin of the MAX-21VZ-R can be carried out with it installed in the vehicle. Be sure to install the aircleaner on the carburetor and to use a mufflerpressurized fuel system. • Now connect glowplug battery lead to heat the plug filament and start the engine. Needle Valve Close The following procedure is suitable for these engines when the O.S.
• When the engine starts, first allow it to operate in short runs at the very rich starting settings, with the glowplug battery still connected and the driving wheels clear of the ground. The rich mixture will, under these conditions, provide adequate lubrication and cooling, indicated by profuse smoke from the exhaust. Needle 30° The position of the needle-valve when starting the engine. 30 ° 30° Close the needle-valve approx. 30˚ after running the vehicle for one full tank of fuel.
IF THE ENGINE FAILS TO START FINAL ADJUSTMENT Check the following: ◆ Glowplug battery discharged or glowplug defunct. ◆ Run the vehicle (with 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 30˚ 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.
Warning! Mixture adjustments (whether via the Metering Needle, 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 engine running, close the throttle and allow it to idle for about five seconds, then reopen the throttle fully.
CARBURETOR CLEANLINESS Ball Link Carburetor Body The correct functioning of the carburetor depends on its small fuel orifices remaining clear. (See Care and Maintenance section on Page17.) Metering Needle First rotate the Metering Needle until its slotted head is flush with the carburetor body. This is the standard position.
Warning! Do not attempt to turn the engine with the starter if the engine is over-primed (flooded) with fuel. To do so is likely to seriously damage the engine. BEFORE STARTING THE ENGINE 1. Before starting the engine for the first run of the day, remove the glowplug and check the engine by rotating the flywheel by hand. It should rotate smoothly. Now turn the engine with an electric starter until fuel is drawn into the carburetor.
inside the engine. Repeat this procedure until the engine fails to fire. Do this while the engine is still warm. GUARANTEE This engine is constructed from the very best materials available and to the very highest engineering standards, using the most advanced precision machinery.
ENGINE EXPLODED VIEW C.M3X16 1-1 1 r 1-2 18 w 2 6 3 4 5 4 7 C.M2.6X7 e 8 C.M2.
ENGINE PARTS LIST No. Code No. 1 23754600 1-1 1-2 23754620 23754610 2 23753000 Cylinder & Piston Assembly 3 23906000 23817000 Piston Pin Retainer(2pcs.
CARBURETOR EXPLODED VIEW & PARTS LIST 2-1 2-2 2 2-3 2-4 3 4 1-1 1-2 6 5 6-1 1 7 9 8 S.M3X3 ✽ Type of screw C…Cap Screw M…Oval Fillister-Head Screw F…Flat Head Screw N…Round Head Screw S…Set Screw No. Code No. 1 23781600 1-1 46066319 1-2 22781800 2 23618190 2-1 23618197 2-2 46066319 2-3 23618194 2-4 23818176 3 23818500 4 23781100 5 23781200 6 23781610 6-1 27881820 7 22884220 8 23781400 9 29015019 Description Mixture Control Valve Assembly "O" Ring(L) (2pcs.) "O" Ring(S) (2pcs.
RACING ENGINE PARTS O.S.
THREE VIEW DRAWING SPECIFICATIONS 37 49.6 3.46 cc(0.211cu.in.) 16.6 mm(0.654in.) 16.0 mm(0.630in.) 3,000-42,000 r.p.m. 2.5 bhp / 34,000 r.p.m. 315.5g(11.14oz.) 4-φ3.3 21 99 83.7 UNF 1/4 -28 27.5 20K JAPAN 15.3 ■ Displacement ■ Bore ■ Stroke ■ Practical R.P.M. ■ Power output ■ Weight 30.8 29.6 43.
L I TY PRECISION & P QUA ERF ED OR M TA BL NC ES E E ANC UNEQ UA LL ISH LE EL ING THE STAN RDS OF EXC DA 6-15 3-Chome Imagawa Higashisumiyoshi-ku Osaka 546-0003, Japan TEL. (06) 6702-0225 FAX. (06) 6704-2722 URL : http://www.os-engines.co.jp C Copyright 2001 by O.S.Engines Mfg. Co., Ltd. All rights reserved. Printed in Japan.
