O.S. Engines 21XZ-R - Manual (Page 10)

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STARTING THE ENGINE & RUNNING-IN ('Breaking-in)
PRESSURIZED FUEL SYSTEM Before starting the engine, always
check the tightness of all the screws
and nuts especially those of joint and
movable parts such as throttle arm.
Missing retightening the loose screws
and nuts often causes the parts break-
age that is capable of harming you.
Never run your vehicle without installing the
air cleaner. Dust and dirt that may otherwise
be drawn into the engine will rapidly shorten
its life.
The somewhat violent changes of vehicle
attitude that occur in off-road running,
combined with the fact that, in buggy type
cars, the fuel tank is often located some
distance from the carburetor, means that the
fuel 'head' at the carburetor can vary and
upset running.Therefore,it is recommended
that a muffler pressurized fuel feed system be
used.
Running- in is a procedure for an engine to
come close to actual running conditions
(fuel, r.p.m., engine temperature, etc.).
Excessively rich running and prolonged
low speed running should be avoided.
Prolonged low speed running and low
temperature running may result in the oil in
the fuel becoming gelled and the
piston/liner becoming stuck together.
RUNNING-IN ('Breaking-in)
19
The following procedure is suitable when a
fuel containing 25% nitro-methane is used.
Fill the tank completely with fuel.
Temporarily remove the glowplug to check
that it glows bright red when energized.
Glow Plug Igniter
Pliers
Element glows when energized.
Replace the plug when the
element does not glow or is
burnt out.
Turn the needle-valve clock-
wise until it stops. This is the
fully closed position.
Do not force it to turn further.
Needle Valve
Open
Close (clockwise)
approx 0.5mm
The carburetor is set at the factory as shown
at the right. Start the engine as it is.
The needle-valve is set approx. 3 turns
opened from the fully closed position.
Throttle is set approx. 0.5mm open.
Approx. 0.5mm open
factory setting with the
reducer removed
Metering needle and mixture control valve
are set at basic position. (Refer to P25.)