O.S. engine FS-70S User Manual

remove the needle-valve holder from the carburettor, using
the wrench supplied, and extract any remaining foreign
matter that may have lodged in the location shown in
Photo 3.
VALVE CLEARANCE ADJUSTMENT
Valve clearances are correctly set before any O.S. four-
stroke engine leaves the factory and, in normal use, will
seldom require adjustment. However, if, after a considera-
ble amount of running time has accumulated, a loss of
power is detected, or if the engine has to be disassembled or
repaired as a result of a crash, valve clearances should be
checked and readjusted as necessary. For checking and
adjusting the valve clearances, a valve adjusting kit, contain-
ing two feeler gauges and two wrenches, is available as an
optional accessory.
Note: Valve clearances on this engine must be checked and re-set
only WHEN THE ENGINE IS COLD.
1. Remove the rocker cover by unscrewing two Allen
screws from the rocker box on top of the cylinder head.
2. Turn propeller until compression is felt, then turn it one
quarter turn and stop. Both valves should now be closed.
3. The required valve clearance is between 0.04 mm and
0.10 mm (.0015 to .004 in.) measured. between the valve
stem and rocker-arm. Use the 0.04 mm (thinner one)
and 0.10 mm (thicker one) feeler gauges to check
clearance. The 0.04 mm feeler should pass through the
gap: the 0.10 mm gauge should not.
4. If the gap is found to be less than 0.04 mm or more than
0.10 mm, carefully slacken the locknut on the rocker-
arm with the 5 mm wrench supplied, turn adjusting
screw with 1.5 mm Allen key to open or close gap, then
retighten locknut.
Finally, re-check gap and readjust if necessary.
IMPORTANT: Incorrect valve clearances may cause. difficult
starting (due to valve not closing property) or loss
of power (due to valve not opening sufficiently).
NEEDLE VALVE EXTENSION
The needle-valve supplied with this engine is designed to in-
corporate an extension so that, when the engine is enclosed
within the fuselage, the needle-valve may be adjusted from
the outside. An L-shaped rod, of 1.6 — 1.8 mm dia. and
appropriate length, should be inserted into the needle’s
centre hole and secured by tightening the set-screw in the
needle-valve knob with the small Allen key provided.
CARE AND MAINTENANCE
To ensure that you obtain long life and peak performance
from your engine, observe the following.
1. Avoid running the engine under dusty conditions. If
necessary, lay a sheet of plywood or hardboard tn front
and under the nose of the model when starting the
engine.
2. Foreign matter in the fuel can cause the carburettor jet
to be partially clogged. Therefore:
e rinse out the fuel tank with methanol or fuel before
installing it
e fit a fuel filter in the fuel delivery tube between tank
and carburettor
ə fit a fuel filter to the outlet of your squeeze bottle, or
to the pump inlet if you use a manual! or electric pump
e do not leave your fuel container open needlessly
e check filters periodically and clean them when necessary.
3. Do not leave raw fuel in the engine at the conclusion of
a flying session: it may cause corrosion. The best practice
is to disconnect the delivery tube from the carburettor
while the engine is running.
Remaining fuel in the tank should also be drained off.
IMPORTANT: After the engine has run dry, liberally inject
corrosion-inhibiting oil or light machine oil into
the crankcase, via the breather hole, until excess oil
runs from behind the drive washer when the engine
is pointed downwards. Rotate the crankshaft to
distribute the oil to the bearings, etc. Failure to
carry out this procedure may cause internal rusting,
resulting in engine malfunction and voiding the
warranty.
4. Clean the exterior of the engine with a clean cotton
cloth. If this is not done, oil and dirt will burn onto the
outside of the engine each time it is run and the engine
will soon become blackened.
5. If the engine is not to be used for a while (more than
two months) remove the glowplug and rinse out the
interior with kerosene (not gasoline), by rotating the
crankshaft. Shake out residue, then inject corrosion-
inhibiting ol or light machine-oi through the exhaust
pipe and breather hole, again rotating the shaft to distri-
bute the protective oil to all working parts.
6. Avoid unnecessary dismantling of your engine.
PARTS LIST
Code No. | Description || Codeno. | Description
44001000 | Crankcass [| 25960000 | intake Valve Assembly
44002000 | Crankshatt | 45361000 | Rocker Arm Assembly
44003200 Piston | 45962000 Camshaft
45103400 Ee a ae A 45564000 Cam Follower
44004000 | Cylinder Head (w/Valve Ass'y) || 44066000 Push Rod
44004100 | Cylinder Heaa || 44066100 Push Rod Cover Assembly
45904200 | Rocker Cover || 24069400 | _ Intake Pipe Assembly
45605000 | Connecting Rod || 24081000 | Carburettor Complete
44006000 | _Piston Pin == 45484000 | Choke Valve Assembly
44008000 | Drive Washer (w/Key) | 71615009 | Glow Plug Type “F”
29008219 | Woodruff Key [| "71905000 | Radial Motor Mount
46120000 | Thrust Washer || "72200060 | Valve Adjusting Kit
45910100 | Safety Propeller Locknut Assembly || *72108100 | Flexible Exhaust Pipe 1111A (120mm)
45913000 | Screw Set || *72108110 | Flexible Exhaust Pipe 1111B (240mm)
44014000 | GasketSet || *72108120 | Flexible Exhaust Pipe 1111C (170mm)
26731002 | Crankshaft Bearing (Front) || *72108130 | Flexible Exhaust Pipe 1111D (330mm)
45630000 | Crankshaft Bearing (Rear) | "45910200 | Locknut Set for Spinner
45231100 | Camshaft Bearing || *45910300 | 5716-M5 Locknut Set
The specifications are subject to alteration for improvement without notice.
GS. Ej NGINE: § MF6.CO.,LTO.
6-15 3-chome Imagawa Higashisumiyoshi-ku
Osaka 546, Japan. TEL. (06) 702-0225
FAX. (06) 704-2722
*Optional parts
© Copyright 1988 by O.S. Engines Mfg. Co., Ltd. All rights reserved. Printed in Japan.
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O.S. engine FS-70S Specifications

General

Brand	O.S. engine
Model	FS-70S
Category	Engine
Language	English