Integrated with O.S. Demand Regulator System 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.
! • NOTES • After starting the engine, carry out any needle- This engine was designed for model helicopters. Do not attempt to use it for any other purpose. valve readjustments after stopping the rotor by closing the throttle to the lowest r.p.m.. Stop the engine before attempting to make other adjustments to the carburetor. • Mount the engine in your model securely, fol- lowing the manufacturers' recommendations, using appropriate screws and locknuts. • Use an electric starter.
Notes on installing cooling fan and clutch Do not use a tool which locks piston when installing a cooling-fan and clutch, or top of the piston may be damaged. Also, do not insert a screw driver or the similar into the exhaust port. It is recommended to use Crankshaft Clamp 91 (Code No.71530510) available as an optional tool. With this engine, the cover plate cannot be removed when the piston is at BDC due to engine construction.
NOTES WHEN APPLYING AN ELECTRIC STARTER Because of the initial tightness, of the piston/sleeve assembly a standard electric starter may have difficulty in rotating the engine when cold, before it has been adequately run-in. In this case, use a high-torque type starter. Do not over-prime. This could cause a 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.
Note on heating the glow plug Example The heatsink head and the crankcase of on the engine is treated with an anodized finish which does not conduct current. Therefore, when heating the glow plug, connect one lead to the glow plug and the other to the cover plate retaining screw. 10 INTRODUCTION This is the O.S. SPEED version of the 91HZ-R developed expressly for the F3C flights.
ENGINE PARTS NAME Glowplug Heatsink Head Throttle Lever Idle Mixture Control Screw Carburetor Typr 61F Fuel Inlet High Speed Needle Valve Thermo Insulater Mixture Control Valve Stopper Mixture Control Valve Cover Plate Thrust Washer Crankcase Beam Mount Reguretor Medium Speed Needle Valve Carburetor Rubber Gasket Propeller nut Crankshaft 12 BEFORE STARTING Tools, accessories, etc.The following items are necessary for operating the engine. In case of 1.
Fuel Fuel Pump Select, by practical tests, the most suitable fuel from among the best quality fuels available in your country for helicopter use. For the best throttle response, a fuel containing 10% to 30% nitromethane is preferable. Lubricants may be either castor-oil or a suitable synthetic oil (or . a blend of both) provided that they are always of top quality. For consistent performance and long engine life, it is essential to use fuel containing AT LEAST 18% lubricant by volume.
INSTALLATION OF THE ENGINE The under-surfaces of all O.S. engine beam mounting lugs are precision machined flat and exactyly parallel to the engine's horizontal axis. It is essential that the engine mounts in the model are also accurately made and aligned. If they are not, they will cause stress and distortion within the engine itself, probably resulting in loss of performance and internal damage.
ABOUT THE NEEDLE CONTROL ARM How to install It is not always necessary to install the needle control arm 1. Remove the high speed needle taking care not to damage it’s point. Note: In order to use this Needle Control Arm , an additional servo and a linkage rod are required. 2. Install the control arm on the needle with a M2.6x5 bolt supplied.
4. Close the high speed needle by moving the transmitter stick travel while actually flying the model. It is suggested for safety to carry out this adjustment after landing the model specially when you are not accustomed with it’s operation. 5. If the engine runs rich even if the transmitter stick travel is moved fully in the direction the high speed needle closes, stop the engine and remove the control arm from the high speed needle. Remember the opening of the high speed needle at this time. 6.
ABOUT THE REGURETOR CARE OF REGURETOR ALWAYS use fuel filters. Keep the fuel tank scrupulously clean and filter all fuel as it enters the tank (e.g.via an O.S.'SuperFilter' Code No.72403050) and use a good quality in-line filter between the tank and regulator. Remember to inspect filter screens at regular intervals and rinse clean as necessary. NEVER disassemble the pressure regulator. Their original performance may not be restored after reassembly.
Fuel Stopper (commercially available) Remove when refuelling Check valve Grooved part should face the fuel tank. T Nipple (commercially available) JAPAN Check valve Be aware of direction Fuel tank Silicone tubing (commercially approx.
CARBURETOR CONTROLS C The Medium Speed Needle Valve This is an extra control that can be brought into play, if necessary, after adjusting A and B above. It provides the means of fine-tuning mixture strength over that all-important part of a helicopter's throttle range where the model is flying in, or near, the hovering mode. With a fixed-wing model, power failure is rarely a serious threat to the safety of the aircraft since it can usually glide down to a safe landing.
STARTING Be sure to use an electric starter to start the engine. ! Element glows when energized. Pliers Never fail to check the tightness of screws and nuts, especially engine mounting and moving parts (e.g. throttle lever). Replace the plug when the element does not glow or is burnt out. Starting procedure is as follows: 1. Fill the fuel tank with fuel. When filled, prevent the fuel from flowing into the carburetor with a commercially available fuel stopper, etc.
5. Inserting the starter shaft Insert the starting shaft into the shaft cup securely. Hold the rotor head by hand so that rotor cannot rotate when the engine is Started. Also, steady the model with a foot on the landing gear skid. 8. Starting Connect the battery to the glowplug and start the engine by applying the starter. When started, switch off the starter and withdraw the starting shaft after making sure the rotation of the starter shaft stops. 6.
RUNNING-IN ("Breaking-in") All internal-combustion engines benefit, to some degree, from extra care when they are run for the first few times known as running-in or breaking-in. Main needle is set two and half turns open from fully closed position and the medium speed needle is set one turn open from fully closed position when the engine leaves the factory. This allows the working parts to mate together under load at operating temperature.
ADJUSTMENT PROCEDURE As a safety measure, first check the transmitter controls, including the throttle stick and trim lever positions, and hold the main rotor securely before starting the engine. This condition may also be initiated by an excessively prolonged warming-up period. lf, on the other hand, the mixture is too Iean, this wiIl be indicated by a marked lack of exhaust smoke and a tendency for the engine to cut out when the throttle is opened.
5. Now re-check hovering performance It may be found that (with the High-Speed Needle Valve now set for optimum full-throttle performance) hovering will reveal symptoms of slightly lean running at medium speeds. DO NOT touch the High-Speed Needle Valve. 3. Now adjust the High-Speed Needle Valve to achieve the best performance when the model is flying at full throttle.
Idling OK Turn the Idle Mixture Control Screw clockwise 5 degrees Rich mixture Land the model Hovering OK Close the High Speed Needle Valve (Turn clockwise) Rich mixture 39 Idling OK Turn the Idle Mixture Control Screw clockwise 5 degrees Rich mixture Fine tuning of idling mixture Close the High Speed Needle Valve (Turn clockwise) Rich mixture Turn the Idle Mixture Control Screw clockwise 5 degrees Open the Medium Speed Needle Valve Adjustment completed Hovering OK Close the Medium Speed Ne
CARE AND MAINTENANCE Please pay attention to the matters described below to ensure that your engine serves you well in regard to performance, reliability and long life. Install an in-line fuel filter between the tank and carburetor to prevent foreign matter in the tank from entering the carburetor. Clean these filters periodically.
TROUBLE SHOOTING Symptom Engine fails to fire. Corrective action Cause Fuel tank is empty. Fuel not reaching the engine. Fill the tank with fuel and repeat. Priming procedure. Glowplug element is burnt out. Glowplug battery discharged Replace glowplug. Recharge or replace the battery. Clogged fuel filter. Silencer inside is dirty. Clean or replace fuel filter. Clean inside silencer. Over priming Remove glowplug and pump out excess fuel. Fuel tubing is disconnected.
Symptom Unstable idle Corrective action Cause Unsuitable glowplug Use suggested glowplug in the instructions. Unsuitable fuel Do not use extremely high nitro or low oil fuel. Silencer is disconnected or is loose Install silencer securely. Symptom Not reaching expected peak r.p.m. Corrective action Cause Insufficient warming up or running-in. Set the needle only after warming up. Complete running-in. Silencer or manifold is not securely connected or disconnected.
47 29074040 29061405 29073110 29503400 29073200 26606008 27917000 29505010 29088030 45010002 46120000 26731002 29081720 45566310 29071010 27930000 29072010 29061410 29067030 22681953 71608001 72403070 29061406 71705110 79871010 Heatsink Head Head Gasket (0.1mm) Cylinder Liner Piston Ring Piston Piston Pin Piston Pin Retainer (2pcs.
CARBURETOR EXPLODED VIEW C.M3x8 3 3-1 C.M2.6x7 1-1 10 5 1 10-1 2 4-3 7 6 8 6-1 4-2 4-1 11-4 11-2 12 9-4 C.M2x5 11-3 9-2 9-3 9-1 9 11-1 11 Type of screw 4 C...Cap Screw 48 CARBURETOR PARTS LIST No. Code No. 1 1-1 2 3 3-1 4 4-1 4-2 4-3 5 6 6-1 7 8 29085140 79871110 29088240 25881220 79871020 29088320 27881810 27881800 27881820 45581820 29088130 27984900 27881330 27681340 Description Throttle Lever Assembly Retaining Screw (10pcs.
O.S. GENUINE PARTS & ACCESSORIES GLOWPLUG No.7 (71607100) CRANKSHAFT CLAMP 91 NON-BUBBLE WEIGHT (71530510) (71531000) NON-BUBBLE WEIGHT S (71531010) No.8 (71608001) No.10 (Former A5) (71605100) LONG SOCKET WRENCH WITH PLUG GRIP LOCK WASHER (10set) M4 (55500003) SUPER FILTER (L) (72403050) (71521000) The specifications are subject to alteration for improvement without notice. 50 THREE VIEW DRAWING 25 SPECIFICATIONS 4- 4.2 52 14.95 cc (0.912 cu.in.) 27.7 mm (1.091 in.) 24.8 mm (0.976 in.
MEMO 52 6-15 3-Chome Imagawa Higashisumiyoshi-ku Osaka 546-0003, Japan TEL. (06) 6702-0225 FAX. (06) 6704-2722 C Copyright 2011 by O.S.Engines Mfg. Co., Ltd. All rights reserved. Printed in Japan.
