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, following 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 similar into the exhaust port. 6 It is recommended to use Crankshaft Clamp 37 (Code No.71530600) available as an optional tool. It is made of durable engineering plastic and locks the crankshaft without risk of damage to any part of the engine.
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 a rag to prevent pumped out fuel getting into your eyes. 8 INTRODUCTION BEFORE STARTING This is a high performance engine designed for small-sized radiocontrolled helicopters.
Fuel 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.
LONG SOCKET DRIVER WITH PLUG GRIP Recommended for easy removal and replacement of the angled and recessed glowplug, the O.S.Long Socket Wrench incorporates a special grip. 8mm End Wrenches 8mm, 13mm, 14mm, etc.
FACTS ABOUT GLOWPLUGS Since the compatibility of glowplug and fuel may have a marked effect on performance and reliability, it may be worthwhile to choose the R/C type plug found most suitable after tests. Recommended O.S. plugs are No.8, A5 and A3. Carefully install plug finger-tight, before final tightening with the correct size plug wrench. However, plug life can be extended and engine performance maintained by careful use, i.e.: Install a plug suitable for the engine.
CORRECT Front view Side view Top surfaces are in the same plane. Make sure that only the under-surfaces of the engine’s mounting lugs are in contact with the engine mount. Please note that crankcase volume of the 37SZ-H is a little larger than the 32SX-H’s. If the crankcase body touches the mount, chamfer the edges of the mount. INCORRECT Top surfaces are not in the same plane. Top surfaces are not in the same plane. Engine does not rest firmly.
Graduations on the carburetor body Fully opened position STARTING Be sure to use a muffler pressurized fuel feed. Use the same fuel as you intend to employ for actual operation of your model. Approx. 1. Opening and closing of the Needle-Valve Fully closed position Turn the needle clockwise to close the needle-valve, and turn the needle counter-clockwise to open the needle-valve as shown in the sketch. Carburetor Body Carburetor Rotor As shown in the sketch, the carburetor has graduation marks.
NOTE: If the throttle response is poor or the engine stops due to a temporarily over-rich mixture immediately after the engine is started, pinch the fuel line for one or two seconds until the engine r.p.m. increase and the engine runs steadily. RUNNING-IN ("Breaking-in") All internal-combustion engines benefit, to some degree, from extra care when they are run for the first few times ーknown as running-in or breaking-in. This is allows the working parts to mate together under load at operating temperature.
H Hover the model and actuate the throttle to observe response over the medium speed range. lf the engine smokes excessiveIy and throttle response is poor, the mixture is too rich ; in which case, land the model and turn the Needle Valve clockwise. Do not close the NeedIe Valve too much, keeping it a little on the rich side at this stage. D lf, at this time, the engine is slow to pick up and produces an excess of exhaust smoke, the mixture is too rich.
SUBSEQUENT READJUSTMENTS CARBURETOR CLEANLINESS Once the engine has been run-in and the carburetor controls properly set up, it should be unnecessary to alter the mixture settings, except to make minor adjustments to the Needle Valve occasionally, to take account of variations in climatic condisitions.
ADJUSTING CHART A Open the Needle Valve 1.5 turns from the fully closed position. Make sure that the Mixture Control Valve is at the factory setting.
INSTALLATION OF THROTTLE SERVO After the engine in the helicopter, please observe the following recommendations when linking the throttle servo to the carburetor. Servo output arm Throttle arm Throttle control rod A and B should be equal of length. Set the linkage so that the servo output arm and throttle arm become parallel when the throttle stick on the transmitter is at middle position. If differential throttle movement is required, make necessary adjustment at the transmitter.
Symptom TROUBLE SHOOTING 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 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.
ENGINE EXPLODED VIEW ENGINE PARTS LIST C.M3x15 1 0.2mm 17 2 15 3 33 32 5 4 6 7 C.M2.6x7 16 8 14 N.+M3.5X5 13 12 9 10 11 ＊Type of screw C…Cap Screw M…Oval Fillister-Head Screw F…Flat Head Screw N…Round Head Screw S…Set Screw No. Code No.
CARBURETOR EXPLODED VIEW C.M3x8 5 4 1-1 3 5-3 1 5-1 5-6 2 5-4 5-5 5-2 N.+M3.5x5 6-2 6-1 7 6 ＊Type of screw C…Cap Screw M…Oval Fillister-Head Screw F…Flat Head Screw N…Round Head Screw S…Set Screw 8 34 CARBURETOR PARTS LIST No. Code No.
O.S. GENUINE PARTS & ACCESSORIES GLOWPLUG DRIVE HUB (23408000) No.8 SUPER FILTER CRANKSHAFT CLAMP 37 (71530600) (L) (72403050) (71608001) A3 (71605300) A5 (71605100) LONG SOCKET WRENCH WITH PLUG GRIP (71521000) CAP SCREW SET LOCK WASHER (10set) M2.6x7 (10pcs.) (79871020) M3 (55500002) The specifications are subject to alteration for improvement without notice. 36 7.5 7.5 THREE VIEW DRAWING SPECIFICATIONS 38 6.07 cc (0.370 cu.in.) 20.5mm (0.806 in.) 18.4mm (0.725 in.) 2,000-21,000 r.p.m.
MEMO 38 6-15 3-Chome Imagawa Higashisumiyoshi-ku Osaka 546-0003, Japan TEL. (06) 6702-0225 FAX. (06) 6704-2722 URL : http://www.os-engines.co.jp C Copyright 2004 by O.S.Engines Mfg. Co., Ltd. All rights reserved. Printed in Japan.
