User manual OS ENGINES FL-70

[. . . ] 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. · 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 aircraft, radio control equipment, etc. , are accessible for checking at the same time. CONTENTS SAFETY INSTRUCTIONS AND WARNINGS ABOUT YOUR O. S. [. . . ] Turn the prop counter-clockwise slowly to locate the position where compression is felt. At this position, fit the prop horizontally and tighten firmly the prop nut with a 13mm wrench. Add the specially tapered and slotted locknut and secure with a 10mm wrench while holding the prop nut with the 13mm wrench. Propeller Washer Lock Nut Propeller Nut 4. Fit a spinner assembly to start the engine with an electric starter. 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). IMPORTANT Regardless of the type of propeller fixing used, make a habit of always checking the tightness of the propeller before starting the engine. Remember that, especially with wooden propellers, there is a tendency for the material to shrink, or for it to be reduced by the serrated face of the drive hub. 23 GLOWPLUG The FL-70 supplied with an O. S. Type F glowplug, specially designed for O. S. The role of the glowplug With a glowplug engine, ignition is initiated by the application of a 1. 5-volt power source. When the battery is disconnected, the heat retained within the combustion chamber remains sufficient to keep the plug filament glowing, thereby continuing to keep the engine running. Ignition timing is 'automatic' : under reduced load, allowing higher rpm, the plug becomes hotter and, appropriately, fires the fuel/air charge earlier; conversely, at reduced rpm, the plug become cooler and ignition is retarded. Use fuel containing a moderate percentage of nitromethane unless more is essential for racing events. Do not run the engine too lean and do not leave the battery connected while adjusting the needle. When to replace the glowplug Apart from when actually burned out, a plug may need to be replaced because it no longer delivers its best performance, such as when: Filament surface has roughened and turned white. Foreign matter has adhered to filament or plug body has corroded. Starting qualities deteriorate. Glowplug life Particularly in the case of very high performance engines, glowplugs must be regarded as expendable However, plug life can be extended and engine performance maintained by careful use, i. e. : 24 TYPE 60W CARBURETTOR Two adjustable controls are provided on this carburettor. They are as follows: The Needle Valve This is used to establish the fuel/air mixture strength required for full power when the throttle is fully open. Needle Valve STARTING The FL-70 is not equipped with manual choke controls, as it is intended for use with an electric starter only. A high-torque electric starter not only makes starting the engine easier, it dispenses with the need for a choke valve by turning the engine over fast enough to cause the fuel pump to prime the cylinder automatically. Starting procedure is as follows: 1. Fill the fuel tank with fuel. When filled, prevent fuel flowing into the carburetor with a commercially available fuel stopper, etc. [. . . ] · If these precautions are neglected, restriction of fuel flow may cause the engine to cut out, or the fuel/air mixture to become too lean causing the engine to overheat. · The use of modern high-performance alcohol based model engine fuels, while promoting cooler running, improved anti-detonation combustion and increased power, has the disadvantage of causing bottom end corrosion in a four-stroke engine. This is due to the acidic by products of combustion that accumulates in the engine's crankcase and are not flushed out by fresh air/fuel mixture as in the case of a two-stroke engine. 36 The use of nitromethane in the fuel can also contribute to the problem. [. . . ]