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.
CONTENTS SAFETY INSTRUCTIONS AND WARNINGS ABOUT YOUR O.S. ENGINE CARBURETOR CLEANLINESS 2~5 15 INTRODUCTION, BASIC ENGINE PARTS 6 BEFORE STARTING THE ENGINE CARE AND MAINTENANCE INSTALLATION 7 GUARANTEE 18 AIR CLEANER TYPE 202 8 THREE VIEW DRAWING 19 GLOWPLUG 9 EXPLODED VIEW 20 ENGINE PARTS LIST 21 CARBURETOR EXPLODED VIEW & PARTS LIST 22 O.S. GENUINE PARTS & ACCESSORIES 23 MEMO 24 TOOLS, ACCESSORIES, etc.
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. • Fit 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-21RZ-R(P) is high performance 3.5cc class power units for one-eighth-scale radio-controlled '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.
INSTALLING THE GLOWPLUG Fit washer to glowplug and 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.
• Position the air cleaner correctly, so that it does not AIR CLEANER TYPE 202 foul the cylinder-head or obstruct the needle-valve. This is a heavy-duty wet type air cleaner that has been developed specifically for the latest 3.5cc 'track-racing' model car engines.
• 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 R5. 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.
LONG SOCKET WRENCH CARBURETOR CONTROLS Recommended for easy removal and replacement of the angled and recessed glowplug, the O.S.Long Socket Wrench incorporates a special grip. Three adjustable controls are provided on this carburettor. The Needle-Valve: For adjusting the mixture strength when the throttle is fully open. ¡ ¡ SILICONE FUEL LINE Heatproof silicone tubing of approx. 5mm o.d. and 2mm i.d. is required for the connection between the fuel tank and engine.
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-21RZ-R(P) can be carried out with it installed in the vehicle. Be sure to fit the air-cleaner to the carburetor and to use a muffler-pressurized 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˚ • Next, disconnect the glowplug battery and try running the car on the track.
◆ Having established the optimum Needle-Valve setting, check the Mixture Control Valve setting as follows. IF THE ENGINE FAILS TO START Check the following: ◆ Glowplug battery discharged or glowplug defunct. ◆ Fuel not reaching carburetor. ◆ Engine flooded. Do not over-prime. (This could also cause hydraulic lock and damage the engine on application of the electric starter.) Remove glowplug, close needle-valve and apply starter to pump out surplus fuel.
Warning! Mixture adjustments (whether via the Mixture Control Valve, 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. CARBURETOR CLEANLINESS The correct functioning of the carburetor depends on its small fuel orifices remaining clear. (See Care and Maintenance section on Page17.
■ REALIGNMENT OF MIXTURE CONTROL VALVE BEFORE STARTING THE ENGINE In the course of making carburetor adjustments, it is just possible that the Mixture Control Valve may be inadvertently screwed in or out too far and thereby moved beyond its effective adjustment range.Its basic position can be found by first rotating the Mixture Control Valve until its slotted head is flush with the carburettor body. The valve is then screwed in exactly 1 turn to re-establish its neutral position. 1.
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. inside the engine. Repeat this procedure until the engine fails to fire. Do this while the engine is still warm. 4. 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. CARE AND MAINTENANCE 1.
GUARANTEE This engine is constructed from the very best materials available and to the very highest engineering standards, using the most advanced precision machinery. However, the extremely high stresses imposed by car racing operation under very severe conditions, stresses which are exacerbated by the use of powerful fuels containing very high concentrations of nitromethane, constitute hazards which are beyond a manufacturer's control.
THREE VIEW DRAWING Dimensions(mm) 54 3.46 cc(0.211cu.in.) 16.6 mm(0.654in.) 16.0 mm(0.630in.) 3,000~40,000 r.p.m. 2.4 bhp / 30,000 r.p.m. 330g(11.6oz.)(01b) 333g(11.7oz.)(01b(P)) 37 SPECIFICATIONS 4-φ3.3 101 86 21 29.5 UNF1/4-28 15 ■ Displacement ■ Bore ■ Stroke ■ Practical R.P.M. ■ Power output ■ Weight 30.6 22(29.4) 44 101 45 19 21.6 13.
EXPLODED VIEW C.M2.6X12 1 w 6 = 20 2 3 4 C.M2.6X7 4 5 q C.M2.
ENGINE PARTS LIST No. Code No. Description 1 2 3704 010 2 2 3703 010 Cylinder & Piston Assembly 3 2 3906 000 Piston Pin 4 2 3817 000 Piston Pin Retainer(2pcs.
CARBURETOR EXPLODED VIEW & PARTS LIST 3-1 3-2 3 2 3-3 3-4 6 4 7 5 1-1 8 1-2 9 0 1 = C.M2.6X7 ✽ 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.
RACING ENGINE PARTS ■ ■ GLOWPLUG CLAMP 1521 (71530200) T-2030 TUNED SILENCER ■ ■ SUPER JOINT TUBE 21 (72106300) (72106030) R5 (71605200) ■ CRANKSHAFT O.S.
MEMO 24
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.
