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FL-70 FOUR CYCLE ENGINE OWNER'S INSTRUCTION MANUAL It is of vital importance, before attempting to operate your engine, to read the general •SAFETY INSTRUCTIONS AND WARNINGS' section on pages 2-6 of this booklet and to strictly adhere to the advice contained therein.
SAFETY INSTRUCTIONS AND WARNINGS ABOUTYOUR O.S. ENGINE Remember that your engine is not a "toy", but a highly efficient internal- combustion 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.
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WARNINGS Never touch, or allow any object to come Model engine fuel is also highly into contact with, the rotating flammable. Keep it away from open flame, excessive heat, sources of sparks, or propeller and do not crouch anything else which might over the engine when it is ignite it.
NOTES This engine was designed for model If you remove the glowplug from the engine aircraft. Do not attempt to use it for any and check its condition by connecting the other purpose. battery leads to it, do not hold the plug with bare fingers.Use an appropriate tool or a Mount the engine in your model securely, folded piece of cloth.
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NOTES Always check the tightness of the propeller Discard any propeller which has become nut and retighten it, if necessary, before split, cracked, nicked or otherwise rendered restarting the engine, particularly in the unsafe. Never attempt to repair such a case of four-stroke-cycle engines.
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NOTES Adjust the throttle linkage so that the engine For their safety, keep onlookers stops when the throttle stick and trim lever (especially small children) well back (at on the transmitter are fully retarded. least 20 feet or 6 meters) when preparing Alternatively, the engine may be stopped by your model for flight.
ENGINE CONSTRUCTION With this engine, the piston will feel tight at the top of its stroke Piston (TDC) when the engine is cold. Cylinder Liner This is normal. The cylinder bore Is a little tapered. Crankshaft The piston and cylinder are A little tapered designed to achieve a perfect running clearance when they...
NOTES WHEN APPLYING AN ELECTRIC STARTER Do not over-prime. This could cause hydraulic lock and damage the engine on application of the electric starter. If over-primed, remove glowplug, close needle-valve and apply starter to pump out surplus fuel. Cover the head with waste to prevent pumped out fuel coming into your eyes.
INTRODUCTION STANDARD ACCESSOIES The FL-70 is an air-cooled, overhead- Glow Plug Type F valve four stroke engine for model aircraft (fitted with the engine) use. This engine is suitable for trainer, sport and scale models. This engine reduces maintenance by...
BEFORE STARTING FUEL The FL-70 should be operated on a methanol Tools, accessories, etc.The following items are based fuel containing not less than 20% necessary for operating the engine. (volumetric) castor oil, or a top quality synthetic Items necessary for starting...
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Reminder! O.S. Non-Bubble Weight Model engine fuel is poisonous. Do not To prevent the pickup from adhering to allow it to come into contact with the eyes or the tank wall under suction and mouth. Always store it in a clearly marked restricting fuel flow, slots may be filed container and out of the reach of children.
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Spinner than those shown in the table may be used, Since the FL-70 is intended to be but remember that the propeller noise will started with an electric starter, the increase if blade tip is raised, due to higher addition of a spinner assembly for rpm or if a larger-diameter/lower-pitched prop centering the starter sleeve is desirable.
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• TOOLS LONG SOCKET WRENCH WITH PLUG GRIP Recommended easy removal HEX WRENCH replacement of the angled and recessed Necessary for engine installation. glowplug, the O.S.Long Socket Wrench 1.5mm, 2mm, 2.5mm, 3mm opposite side incorporates a special grip. Plus Threaded Drivers No.1,No.2,etc.
INSTALLATION Because the FL-70 is a powerful, large-displacement, single-cylinder four-stroke-cycle engine, it is essential to use very substantial engine mounting. Conventional wooden mounting beams should be of rigid hardwood and of at least 15mm or 5/8-in square section. Make sure that the mounting beams are parallel and that their top surfaces are in the same plane.
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How to fasten the mounting screws. • Make sure that these mounting beams are accurately aligned and firmly integrated with Hardwood mounting beams the airframe, reinforcing the adjacent Tighten second nut structure to absorb vibration. Use 3mm or firmlydown onto first nut. 3mm steel nuts larger steel screws, preferably Allen type Tighten this nut first.
SILENCER & EXHAUST HEADER PIPE INSTALLATION Screw the header pipe into the cylinder head Lock Nut until it "bottoms" , then unscrew sufficiently to achieve the desired exhaust angle and tighten the lock nut securely with a 14mm wrench. Screw the silencer onto the outer end of the header pipe and tighten the other locknut.
FUEL TANK & LINES Piping suitable for acrobatic flights Make sure that the tank is well rinsed out with methanol or glow fuel before installation With the general piping, the fuel in the tank and that the pickup weight is well clear of the may flow into the silencer when the throttle is bottom of the tank when held vertically.
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Note: When cutting silicone tubing, Fig. 1 General Piping use knife or razor blade. No.5 Nipple (smaller hole) Do not use wire cutter Silicone Tubing or pliers. No.1 Nipple (larger hole) If you should need to clean out silicone tubes, use methanol or glow fuel, not gasoline or kerosene.
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Fig. 2 Piping suitable for acrobatic flights No.5 Nipple (smaller hole) No.1 Nipple (larger hole) Install the fuel tank so that carburetor center line and fuel tank center line may come to as much close as possible. Fuel Filter T Nipple (supplied) (commercially available) Fuel Stopper (commercially...
THROTTLE LINKAGE NEEDLE-VALVE EXTENSION The needle-valve supplied with this engine is Before connecting the throttle to its servo, designed to incorporate an extension so that, make sure that the throttle arm and linkage when the engine is enclosed within the safely clear any adjacent part of the airframe fuselage, the needle-valve may be adjusted structure, etc., as the throttle is opened and...
PROPELLER & SPINNER ATTACHMENT There is a risk, particularly with powerful four- 3. Add the specially tapered and slotted stroke engines, of the propeller flying off if the locknut and secure with a 10mm wrench prop loosens detonation while holding the prop nut with the 13mm ("knocking") in the combustion chamber when wrench.
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Note: Some spinners which are fixed at the top of the cone cannot be used with the prop locknut supplied with the engine. In this case, optional locknut sets are available from O.S. - Propeller Locknut Set for Spinner (Code No.45810200) and Propeller Locknut Set for Tru Turn Spinner (Code No.145810300).
GLOWPLUG The FL-70 supplied with an O.S. Type F glowplug, Install a plug suitable for the engine. specially designed for O.S. four-stroke engines. Use fuel containing a moderate percentage of nitromethane unless more is essential for racing The role of the glowplug events.
STARTING TYPE 60W CARBURETTOR Two adjustable controls are provided on this The FL-70 is not equipped with manual carburettor. choke controls, as it is intended for use They are as follows: with an electric starter only. A high-torque electric starter not only...
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3. Check that the current to the glowplug is Element glows when energized. switched off. Pliers Close 4. To close the needle-valve, turn it clockwise, while to open the Open needle-valve, turn it counter- clockwise. Turn the needle-valve Replace the plug when the Close clockwise slowly until it stops.
8. Make sure that the rotating direction of the RUNNING-IN ("Breaking-in") electric starter is correct. Energize the glowplug and apply the starter. For long life and peak performance, every engine needs special treatment when new, 9. When the engine starts, slowly open the know as "running-in"...
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On the contrary, prolonged low speed running 5. Repeat this process, alternately running the may cause the oil in the fuel gelled, which may engine fast and slow by means of the result in seizure of the piston and cylinder liner. needle-valve, while keeping the throttle fully The recommended procedure is as follows: open, then begin to extend the short...
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8. With each successive flight, close the CARBURETOR needle-valve very slightly until, at the end of These engines are equipped with a throttle about 10 flights, the needle is set for full type car-buretor which provides a wide range power. Do not "over-lean" the mixture in an of engine speed control.
Start the engine Make sure that the throttle is fullyopen 20-30' open from maximum Adjust the neede-valve. rp.m setting. Close the throttle gradually The position where the lowest Find the idling position. possible r p m .with steady running, is obtained. Set the throttle opening by Fix the idling position.
CARBURETOR AIR-BLEED ADJUSTMENT Pre-Flight Check Start engine and adjust needle- valve as previouslv described. Close the throttle gradually. Find the idling position. approx 15 degrees Hold the model. Hold model level, then slowly raise the nose. If rpm increases. If engine runs unevenly or stops. Stop the engine.
TROUBLE SHOOTING WHEN THE ENGINE FAILS TO START Four key points For quick, reliable starting, the following four conditions are required. (1.) Good compression. (2.) Adequate "glow" at glowplug. (3.) Correct mixture. (4) Sufficient electric starter rotating speed. If the engine fails to start, or does not keep running after being started, check symptoms against the following chart and take necessary corrective action.
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Corrective action Symptom Factor Cause Incorrect heating of ..Voltage too high or too low. Re-check and readjust referring to "BEFORE Engine fires glowplug. STARTING". Intermittently but Over priming. . . • • • • • • Continue applying an electric starter. II the engine does not start after more does not run.
VALVE ADJUSTING Valve clearances are correctly set before any O.S. engine leaves the factory and, in normal use, will seldom require adjustment. However, if, after a very considerable amount of running time has been consumed, a loss of power is detected, engine been...
HOW TO SET THE CAMSHAFT TIMING The relation of position between ' • ' mark of When replacing the camshaft, set the timing as follows. the gear and teeth may differ from the sketch, by each model. 1. Secure propeller. NOTE: crankcase If propeller is not secured, crankshaft may...
CARE AND MAINTENANCE Please attention matters • Fit an in-line fuel filter between the tank and described below to ensure that your engine carburetor to prevent dist and dust in the serves you well in regard to performance, tank entering the carburetor. reliability and long life.
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• When the engine is not to be used for some The use of nitromethane in the fuel can also months (for example, as between flying contribute to the problem. As a primary seasons), a worthwhile precaution is to defense, users are advised to avoid running remove it from the airframe and, after the engine on too lean a mixture - i.e.
ENGINE EXPLODED VIEW *Type of screw C Cap Screw B..Binding Head Screw M.. Oval Fillister-Head Screw F...Flat Head Screw N. .Round Head Screw S...Set Screw...
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Description Code No Rocker Cover 44404200 Rocker Support Assembly 45961400 Rocker Support 45961410 Rocker Arm Retainer (2pcs.) 45761600 Rocker Arm Assembly (1pair) 44753000 Rocker Arm (1pc.) 44753100 Tappet Adjusting Screw 45761200 44460000 Intake Valve Assembly (1 pair) Intake Valve (1pc.) 44460100 45960210 Valve Spring (1pc.)
CARBURETOR EXPLODED VIEW * Type of screw C Cap Screw B Binding Head Screw M Oval Fillister-Head Screw F...Flat Head Screw N . Round Head Screw S .Set Screw...
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