O.S. Engines 12TZ(P) - Manual (Page 9)

16
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 fuel
'head' at the carburettor can vary and upset
running.Therefore,it is recommended that a
muffler pressurized fuel feed system be used.
Lay the chassis on a stand and start the
engine so that the tiers may not be in
contact with the ground.
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 mean nothing. Prolon-
ged low speed running and low tempera-
ture running may result in the oil in the fuel
being gelled and piston/liner being agglu-
tinated.
Try to make time to run the car at full throttle.
Lengthen full throttle running time gradually.
When the car can run full throttle with rich
mixture at the straight, close the needle-valve
a little. Repeat this procedure until the car runs
at the maximum speed at the latter straight
course.
17
The following procedure is suitable for these
engines when the O.S. T-1040 tuned silencer
and a fuel containing up to 30% nitrome-
thane are 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 clockwise until it stops. This
is the fully closed position. Do not force it to turn
further.
Metering needle and mixture control valve
are set at basic position. (Refer to P23.)
Needle Valve
Open Close (clockwise)
approx 0.5mm
The carburetor is set as shown below at the
factory. Start the engine as it is.
The needle-valve is set approx. 1-3/4 turns
opened from the fully closed position.
Throttle is set approx. 0.5mm open.
Approx. 0.5mm open
factory setting with the
reducer removed