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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.

It is suggested that any instructions supplied 
with the vehicle, radio control equipment, etc., 
are accessible for checking at the same time.

Summary of Contents for max-21RG-M

Page 1: ...ontained 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 It is suggested that any instructions supplied with the vehicle radio control equipment etc are accessible for checking at the same time ...

Page 2: ...tc CARBURETTOR CONTROLS STARTING INITIAL RUNNING IN Breaking in ADJUSTMENT 2 5 6 7 8 8 9 9 10 10 11 13 15 16 17 18 19 20 21 22 28 CARE AND MAINTENANCE CHECKING OF THE ENGINE TROUBLE SHOOTING WHEN THE ENGINE FAILS TO START ENGINE EXPLODED VIEW ENGINE PARTS LIST CARBURETTOR EXPLODED VIEW PARTS LIST O S GENUINE PARTS ACCESSORIES THREE VIEW DRAWING MEMO 12 19 23 24 25 26 27 1 ...

Page 3: ...equest that these instructions are also passed on to its new owner SAFETY INSTRUCTIONS AND WARNINGS ABOUT YOUR O S ENGINE The advice which follows applies basically to ALL MODEL ENGINES and is grouped under two headings according to the degree of damage or danger which might arise through misuse or neglect WARNINGS NOTES These cover events which might involve serious in extreme circumstances even ...

Page 4: ...anyoneelse to smoke near to it Never operate your engine in an en closed space Model engines like auto mobile engines exhaust deadly carbon monoxide Run your engine only in an open area 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 Ne...

Page 5: ...yance to others over a wide area Take care that the glowplug clip or battery leads do not come into contact with the propeller or any other rotating parts Also check that the linkage to the throttle arm is secure If your engine does not have a built in recoil starter use an electric starter The wearing of safety glasses is also strongly recommended When handling the boat immediately prior to launc...

Page 6: ...d over compression WITHOUT the glowplug battery being reconnected NOTES If your engine is fitted with a recoil starter pull the operating handle straight out when starting the engine so that the cord does not rub against the hull or engine This will help prevent the cord from being damaged by abrasion or engine heat Do not extend the starter cord more than 45cm 18 Do not abruptly release the opera...

Page 7: ...ir normal running temperatures We do not recommend running your boat on the sea or in any other saltwater environment Under such conditions it is difficult to prevent the engine from becoming corroded and eventually inoperative NOTE Standard accessories Glow Plug No 8 Flywheel No2E Exhaust Header Pipe BASIC ENGINE PARTS Carburettor Type 20J Water Cooled Head Starter Handle Recoil Starter Assembly ...

Page 8: ...er 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 screw Rotate the retainer screw gently until it stops then tighten a further 90 120 Do not overtighten the screw as this will damage the carburetor body 1 2 Rotate the retainer nut gently until it stops Tighten a further 90 120 Cra...

Page 9: ...for bolting the engine to the mounting beams If the holes in the mounting beams do not align exactly with the engine s mounting lugs enlarge them slightly with a needle file so that the mounting screws pass through the holes smoothly without being forced 1 2 3 Chamfer inside edges of bearers NOTES CONCERNING THE RECOIL STARTER REMINDER Do not attempt to disassemble the recoil starter If you do so ...

Page 10: ...ility it is suggested that the user selects the R C type plug found most suitable after practical experiments Generally for a fuel containing about 30 nitromethane a medium heat range glowplug will be suitable The role of the glowplug With a glowplug engine ignition is initiated by the application of a 1 5 volt power source When the battery is disconnected the heat retained within the combustion c...

Page 11: ...omethaneunlessmoreisessentialforracingevents TOOLS ACCESSORIES etc The following items are necessary for operating the engine FUEL 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 For consistent performance and long engine life it is essential to use a good quality fuel containing NOT LESS T...

Page 12: ...NG SOCKET WRENCH SILICONE FUEL LINE This is required for the connection between the fuel tank and engine also for the water cooling system ELECTRIC STARTER AND STARTER BATTERY Use a 12 volt electric starter with suitable battery for starting the engine 21RG M BATTERY INTEGRATED GLOWPLUG HEATER Commercialy available handy glowplug heater in which the glowplug battery and battery leads are integrate...

Page 13: ...r Needle Valve Mixture Control Valve Mixture Control Screw Throttle Lever Fuel Inlet Rotor Guide Screw REALIGNMENT OF MIXTURE CONTROL VALVE In the course of making carburettor 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 setting can be reestablished as follows Nozzle T...

Page 14: ... muffler pressurized fuel system When starting the engine put the hull on a stand etc out of the water In case of the 21RG M Priming Turn the flywheel by hand to draw the fuel to the fuel inlet Turn the flywheel two more revolutions to draw the fuel inside the engine NOTE IMPORTANT The quantity of fuel drawn into the engine by priming is an important factor in starting the engine successfully When...

Page 15: ... Make sure that the direction of rotation of the electric starter is correct namely clockwise If necessary reverse leads on battery to provide clockwise rotation Hang the starter belt over the flywheel and starter and depress the starter switch for one or two seconds Repeat if necessary When the engine fires withdraw the starter immediately PRECAUTIONS When starting the engine the hull is off the ...

Page 16: ...er to the adjustment procedures detailed later The boat will need to be run or about 10 tanks of fuel to complete the running in period Warm up the engine by running it at around idling setting for a while after starting Note If as a result of your boat being capsized the engine takes in water remove the glowplug invert the engine and eject water by carefully turning the flywheel first by hand and...

Page 17: ...w return the model and close the needle valve 20 to 30 Repeat the run taking note of the improvement in speed Continue with further runs gradually closing the needle valve 20 to 30 at a time until no further increase in speed is obtained If the needle valve is closed beyond the optimum setting the model will slow down accompanied by visibly diminished exhaust smoke In this case immediately throttl...

Page 18: ...engine is operated with the fuel air mixture slightly too lean it will overheat and run unevenly or cut out As with all engines it is wise to set both valves a little on the rich side of the best rpm setting as a safety measure When the best balance of mixture adjustments has been determined and especially as the engine becomes fully run in it will probably be found that the idling speed has incre...

Page 19: ...Remove this with an 8mm spanner Dirt and fibrous matter mostly accumulate here CARE AND MAINTENANCE To ensure that you obtain long life and peak performance from your engine observe the following As previously observed foreign matter in the fuel can cause problems Therefore rinse out the fuel tank with methanol or fuel before installing it Install a fuel filter to the fuel delivery tube between ta...

Page 20: ...or any solvent that might damage the silicone fuel tubing or any plastic parts of the boat hull 4 5 6 When the engine is not in use remove the glow plug and rinse out the interior with kerosene not gasoline by rotating the crankshaft Shake out re sidue then inject light machine oil through the plug hole again rotating the shaft to distribute the pro tective oil to all working parts 7 8 In the even...

Page 21: ...ked with three asterisks the less common problems with one or two asterisks Recharge the electric starter battery Pull the recoil starter briskly Recharge lead acid cell or replace dry battery Note An unused or almost unused dry battery may sometimes be of insufficient capacity if it is old stock Replace glowplug Check that applied voltage is not too high Check glowplug heating using other leads C...

Page 22: ...and wait for several minutes then re start Make sure that tank is filled with fuel Check that there is not something wrong with fuel tubing kinked or split Check that carburettor is not clogged with dirt Close the needle valve a little Change fuel or glowplug Engine fires intermittently but does not run Engine fires once or twice then fails to fire Engine starts but revol utions decrease and en gi...

Page 23: ...2 6X7 C M2 6X18 e w q 0 9 8 7 6 5 4 C M2 6X18 r t A t 1 t 2 y C M2 6X7 M 2 6X7 Type of screw C Cap Screw M Oval Fillister Head Screw F Flat Head Screw N Round Head Screw S Set Screw MAX 21RG M MX EXPLODED VIEW 22 ...

Page 24: ...Rear Adaptor Starting Shaft Crankshaft Ball Bearing Rear Crankcase Crankshaft Ball Bearing Front Carburetor Retainer Carburetor Complete Type 20J Connecting Rod Piston Pin Retainer 2pcs Piston Pin Cylinder Piston Assembly Water Cooled Head Assembly Description Crankshaft Crankshaft Recoil Starter Body No 5 Oneway Clutch No 5 Code No Glowplug No 8 Flywheel No 2E Exhaust Header Pipe The specificatio...

Page 25: ...Lever Assembly Set screw Carburettor Rotor Mixture Control Valve O Ring 2pcs Rotor Spring Carburettor Body Rotor Guide Screw Fuel Inlet Needle Valve Assembly Needle O Ring 2pcs Set screw Needle Valve Holder Assembly Ratchet Spring Carburettor Rubber Gasket The specifications are subject to alteration for improve ment without notice CARBURETTOR EXPLODED VIEW PARTS LIST C Cap Screw M Oval Fillister ...

Page 26: ...002 M3 72106300 72106030 GLOW PLUG T 2030 TUNED SILENCER SUPER JOINT TUBE 21 CRANKSHAFT CLAMP LONG SOCKET WRENCH WITH PLUG GRIP O S GENUINE PARTS ACCESSORIES SUPER FILTER L LOCK WASHER 10sets MARINE UNIVERSAL JOINT 4mm No 8 A5 DUST CAP SET For carburetor nipple For T 2030 tuned silencer 25 ...

Page 27: ...0in 3 000 35 000r p m 1 7ps 28 000r p m 317g 11 18oz JAPAN 21 37 10 5 45 29 6 33 5 4 φ3 3 UNF 1 4 28 67 21 5 88 5 59 5 74 5 MAX 21RG M THREE VIEW DRAWING Displacement Bore Stroke Practical R P M Power output Weight SPECIFICATIONS Dimensions mm 26 ...

Page 28: ...30in 3 000 35 000r p m 1 7ps 28 000r p m 389g 13 72oz JAPAN 40 107 45 29 6 UNF 1 4 28 67 59 5 74 5 21 4 φ3 3 10 5 33 5 37 Dimensions mm MAX 21RG MX THREE VIEW DRAWING SPECIFICATIONS Displacement Bore Stroke Practical R P M Power output Weight 27 ...

Page 29: ...MEMO 28 ...

Page 30: ...eserved Printed in Japan 090100 TEL 06 6702 0225 FAX 06 6704 2722 6 15 3 Chome Imagawa Higashisumiyoshi ku Osaka 546 0003 Japan U N E Q U A LLED QUALITY PRECISION PERFOR M A N C E E S T A BLISHING THE STANDARDS OF EXCELLE N C E URL http www os engines co jp ...

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