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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 2-3 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 model radio control 
equipment, etc., are accessible for checking 
at the same time.

Summary of Contents for MAX-21XM

Page 1: ...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 model radio control equipment etc are accessible for checking at the same time ...

Page 2: ...TALLATION LINKAGES FUEL AND GLOWPLUG FLEXIBLE DRIVE SHAFT PROPELLER BEFORE STARTING THE ENGINE ADJUSTING THE CARBURETTOR REALIGNMENT OF MIXTURE CONTROL VALVE STARTING RUNNING IN Breaking in ADJUSTMENT CARBURETTOR CLEANLINESS CARE AND MAINTENANCE TROUBLE SHOOTING WHEN THE ENGINE FAILS TO START EXPLODED VIEW PARTS LIST CARBURETTOR EXPLODED VIEW PARTS LIST THREE VIEW DRAWING AND SPECIFICATION 1 ...

Page 3: ...hich follows is grouped under two headings according to the degree of damage or danger which might arise through misuse or neglect WARNINGS Never touch or allow any object to come into contact with the rotating propeller 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 eng...

Page 4: ...attery leads do not come into contact with the propeller or any other rotating parts Also check the security of the linkage to the throttle arm When starting your engine use an electric starter The wearing of safety glasses is also strongly recommended When handling the boat immediately prior to launching be especially cautious Keep the propeller and other rotating parts away from you Adjust the t...

Page 5: ... in any other saltwater environment Under such conditions it is difficult to prevent the engine from becoming corroded and eventually inoperative Fit washer to glowplug and insert carefully into cylinder head making sure that it is not cross threaded before tightening firmly INSTALLATION OF THE CARBURETTOR As delivered this engine has its carburettor lightly fitted into its intake boss Secure it a...

Page 6: ...50 Silencer Water Inlet Tube Exhaust Outlets Cooling Water Pickup Carbon Reinforced Propeller Skeg Outboard Unit Lower Housing Cavitation Plate Oil Transfer Tube Transom Mounting Plate Steering Arm Throttle Linkage Bracket Crankcase Throttle Lever Mixture Control Screw Flywheel OS No 2J 5 ...

Page 7: ...ll bend easily which results in poor steering accuracy Throttle Linkage Use flexible Bowden type cable having a 3mm OD outer sleeve Secure one end of the sleeve to the engine by means of the throttle linkage bracket supplied and the other end to any appropriate part of the hull structure immediately sur rounding the throttle servo See sketch If the two ends are not secured in this way steering the...

Page 8: ...s 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 naked 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 Reminder The O S No 8 glowplug is recommended and one is supplied with this engine The MAX 21XM may not always run so well with...

Page 9: ...aft This has squared ends that fit into the PTO shaft at the power head and the propeller shaft at the bottom end Note that the propeller shaft bearing has a left hand thread Fit a plug suitable for the engine e g OS No 8 Use fuel containing a moderate percentage of nitromethane unless essential for racing events Do not run the engine too lean and do not leave the battery connected while adjusting...

Page 10: ...ikely to seriously damage the working parts WARNING ADJUSTING THE CARBURETTOR Two adjustable controls are provided on this carburettor 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 Refer to sketch p 10 top l...

Page 11: ... engine fires withdraw the starter immediately Do not apply the starter to a flooded engine and never place your finger over the carburettor intake when using the starter This may cause an hydraulic lock and bend the connecting rod Adjusting the needle valve adjust the needle valve to its optimum setting only while actually running your boat on the water To stop the engine fully close the throttle...

Page 12: ...d as a reference mark Set the throttle at the starting position i e very slightly opened from idling position and start the engine It is necessary to warm up the engine by running it at around the idling setting for a while after starting as with the engine of a full size boat High r p m operation without warming up will shorten engine life or damage it Leaving the Needle Valve set at the starting...

Page 13: ...omplete the running in as follows WARNING Aim to have the model achieving its highest performance after the engine has consumed about one litre of fuel Having found the optimum needle valve setting make a note of the number of turns necessary to re establish this from the closed position With the engine run in and the optimum needle valve setting determined the mixture control valve should be chec...

Page 14: ...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 15: ...aning the exterior of the engine use methanol or kerosene Do not use gasoline or any solvent that might damage the silicone fuel tubing or any plastic parts of the boat hull When the engine is not in use remove the glowplug and rinse out the interior with kerosene not gasoline by rotating the crankshaft Shake out residue then inject light machine oil through the plug hole again rotating the shaft ...

Page 16: ...ge too high or too low Re check and readjust referring to BEFORE STARTING Continue to apply starter If necessary disconnect battery from glowplug and leave for a few minutes then re energize plug If engine still does not start remove glowplug and pump out excess fuel Then re start Recharge the electric starter battery Recharge lead acid cell or replace dry battery Note An unused or almost unused d...

Page 17: ...3 E 23 F 23 G 23 H 23 I 23 J 23 K 23 L 23 M 24 25 23 23 C1 23 C2 C M3X12 C M2 6X18 C M2 6X18 C M2 6X10 N M3X10 N M3X12 C M3X10 C M2 6X8 F M3X10 N M3X10 C M4X12 N M4X8 C M4X12 F M3X8 13 1 13 2 13 3 Type of screw C Cap Screw M Oval Fillister head Screw F Flat Head Screw N Round Head Screw S Set Screw 16 ...

Page 18: ...ssembly No 2J Flywheel Nut Crankshaft Ball Bearing Outer Crankcase Carburettor Retainer Throttle Linkage Bracket Carburettor Type 20J Connecting Rod Piston Pin Retainer 2pcs Piston Pin Cylinder Piston Assembly Water Cooled Head Assembly Nipple No 2 Screw Set E 2050 Silencer Silencer Assembly Screw 4pcs Nipple No 1 Silencer Fixing Screw 2pcs Crankshaft Ball Bearing Inner Crankshaft Power Take Off S...

Page 19: ...Description Fuel Inlet Needle Valve Assembly Needle O Ring 2pcs Set screw Needle Valve Holder Assembly Ratchet Spring Carburettor Rubber Gasket Code No Description 2 2681 953 2 7881 900 2 4981 959 2 4981 837 2 6381 501 2 7381 940 2 6711 305 2 9015 019 No 7 8 8 1 8 2 8 3 8 4 8 5 9 The specifications are subject to alteration for improvement without notice CARBURETTOR EXPLODED VIEW PARTS LIST 1 1 1 ...

Page 20: ...ical R P M Power output Weight 3 46 c c 0 211 cu in 16 6 mm 0 654 in 16 0 mm 0 630 in 3 000 25 000 r p m 1 3 bhp 25 000r p m 670g 23 6 oz 48 5 37 5 46 45 25 149 5 219 46 34 5 86 183 87 64 48 5 46 SPECIFICATION THREE VIEW DRAWING 19 ...

Page 21: ...MEMO 20 ...

Page 22: ...ghts reserved Printed in Japan U N EQUALLED QUALITY PRECISION PERFORMAN C E ESTABLISHING THE STANDARDS OF EXCELLENC E TEL 06 6702 0225 FAX 06 6704 2722 6 15 3 Chome Imagawa Higashisumiyoshi ku Osaka 546 0003 Japan 100101 URL http www os engines co jp ...

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