Integrated with O.S. fuel 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. 6 Notes on installing cooling fan and clutch Do not grip the engine mounting beams with a vise, or the crankcase will be distorted which will result in engine breaking.
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 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 head or cover plate retaining screw. 10 INTRODUCTION The MAX-91HZ-R has been developed based on the 91HZ designed expressly for 90 size helicopter models, and equipped with the new O.S. regulator system.
ENGINE PARTS NAME Glowplug Heatsink Head Throttle Lever Idle Mixture Control Screw Carburetor Typr 61E-R 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 Pump Fuel Alternatively, one of the purpose-made manual or electric fuel pumps may be used to transfer fuel directly from your fuel container to the fuel tank. 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 .
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.
INSTALLATION OF THE CARBURETOR Note: In case it is hard to insert the carburetor in the crankcase, apply oil on the Thermo Insulater. Do not force it, or damage to the Thermo Insulater and/or crankcase can occur. As delivered, the engine has its carburetor lightly fitted into its intake boss. Secure it as follows. 1. Loosen carburetor retainer screw slightly. 3. Rotate the retainer screw gently until it stops, then tighten a further 90-120 degrees.
ABOUT THE PLUMBING Note: Since the muffler pressurized fuel feed is not used with this engine, plug a nipple on the muffler or replace it with a bolt. Carry out plumbing referring to a sketch on page 21. Connect silicone tubing cut into approx. 10cm to the nipple on the cover plate. Then, connect the check valve supplied with the engine as sketched (Be aware of the direction.) It is suggested to install a stopper as shown in the sketch.
GLOWPLUG Glowplug life Since the glowplug and fuel combination used may have a marked effect on performance and reliability, it would be worthwhile to experiment with different plug types. Recommended O.S. plugs are No.8, No.7 and No.10 (Former A5) . Carefully install plug finger-tight, before final tightening with the correct size plug wrench. Particularly in the case of very high performance engines, glowplugs must be regarded as expendable items.
GRADUATIONS ON THE CARBURETOR BODY BASIC POSITION OF MIXTURE CONTROL SCREW (Mixture Control Valve) As shown in the sketch, the carburetor has graduation marks. As delivered, the Mixture Control Screw is positioned at approximately the center as shown in the sketch. Mixture gets lean when the Mixture Control Screw is turned right, while mixture gets rich when the Mixture Control Screw is turned left.
Medium Speed needle-valve: one turn open from the fully closed position. 1. Opening and closing of the Needle-Valve Turn the needle clockwise to close the needlevalve, and turn the needle counter-clockwise to open the needle-valve as shown in the sketch. 3. Preparation of the starter Install the starting shaft to the starter securely. Improper installation will allow the shaft to swing creating a dangerous situation.
In case the engine does not stop. Hold the rotor head, and pinch the fuel line to stop the fuel supply. If it still does not stop, pull off the fuel line from the carburetor. It is necessary to readjust the throttle linkage so that the carburetor rotor is fully closed when the throttle stick and throttle trim on the transmitter are fully pulled Down.
ADJUSTMENT Please observe the following before beginning to make any adjustment. The general course of adjustment procedure is shown in the ADJUSTING CHART and is correct for a fuel containing 20% lubricant and 15-30% nitromethane. High-Speed Needle Valve. Turn this approximately 30 degrees (3 to 4 clicks) at a time, when making initial adjustments; then in steps of approximately 15 degrees (1 to 2 clicks) when making final adjustments.
After about 10 seconds of idling, open the throttle to 'float' the model. lf the transition is smooth, the idle mixture is O.K. If the symptoms of either rich or Iean running are observed, readjust the Idle Mixture Control Screw accordingly. Maximum 2. Having provisionally set the idle mixture, the next step is to adjust the mixture for hovering flight. Hover the model and actuate the throttle to observe response over the medium speed range.
CARBURETOR CLEANLINESS SUBSEQUENT READJUSTMENTS The correct functioning of the carburetor depends on its small fuel orifices remaining clear. The minute particles of foreign matter that are present in any fuel can easily partially obstruct these orifices and upset mixture strength so that engine performance becomes erratic and unreliable.
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.
43 29074030 29061405 29073100 29503400 29073200 26606008 27917000 29505010 29088000 45010002 46120000 26731002 29081720 45566310 29071000 27930000 29072000 29061410 29067011 22681953 71608001 72403070 29061406 41621100 Description Heatsink Head Head Gasket (0.1mm) Cylinder Liner Piston Ring Piston Piston Pin Piston Pin Retainer (2pcs.
CARBURETOR EXPLODED VIEW C.M3x8 1-1 3 C.M2.6x7 10 5 1 10-1 2 6 4-3 7 8 12 Type of screw 11-3 11-1 11 9-3 9-1 9 CAP SCREW SETS (10pcs./sets) Code No. Size 79871020 M2.6x7 4 C...Cap Screw 9-2 4-2 4-1 11-4 11-2 13 9-4 C.M2x5 Pcs. used in an engine Rotor Guide Washer Retaining Screw (1pc.) 44 CARBURETOR PARTS LIST No. Code No.
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. 46 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 48 URL : http://www.os-engines.co.jp C Copyright 2010 by O.S.Engines Mfg. Co., Ltd. All rights reserved. Printed in Japan. 6-15 3-Chome Imagawa Higashisumiyoshi-ku Osaka 546-0003, Japan TEL. (06) 6702-0225 FAX.
