O.S. Engines 21RG-X - Manual (Page 11)

20
CARBURETOR CLEANLINESS
The correct functioning of the carburetor depends on
its small fuel orifices remaining clear.
(See Care and Maintenance section on Page21.)
BALL LINK AND SLIDE VALVE EXTENSION
When readjusting the position of the Ball Link, always
apply a 6mm spanner (wrench) to the flats in the
Slide Valve Extension, before attempting to loosen or
tighten the ball link retaining screw. Carefully ease
back the Dust Cover bellows to allow access to the
flats. If it should become necessary (e.g. for cleaning)
to disassemble the throttle parts, first unscrew the
Slide Valve guide screw and withdraw the complete
sub-assembly from the carburettor body. Use the
correct size (8mm) wrench when unscrewing the
Slide Valve from the Slide Valve Extension.
'Flats' for spanners
Slide Valve Slide Valve Extension
REALIGNMENT OF MIXTURE CONTROL VALVE
In the course of making carburetor adjustments, it is
just possible that the Mixture Control Valve may be
inadvertently screwed in or out too far and thereby
moved beyond its effective adjustment range.Its basic
position can be found by first rotating the Mixture
Control Valve until its slotted head is flush with the
carburettor body. The valve is then screwed in exactly
1 turn to re-establish its neutral position.
Mixture Control Valve
Carburetor Body
First rotate the Mixture Control
Valve until its slotted head is
flush with the carburetorbody.
Then screw the valve in exactly
1 turn.
This is the standard position.
21
BEFORE STARTING THE ENGINE
1.
2.
Before starting the engine for the first run of the day,
remove the glowplug and check the engine by
rotating the flywheel by hand. It should rotate
smoothly. Now turn the engine with an electric
starter until fuel is drawn into the carburetor. At first,
rotation may feel 'sticky' due to oily residue
remaining within the engine. The engine should
rotate freely after fresh fuel has been drawn into the
working parts.
Check the glowplug. If the plug element is distorted,
off-center, or has a white appearance, engine
performance may be below par. With racing type
engines, glowplugs have to be regarded as
consumable items. Therefore, replace the plug if
necessary.
3.Re-install the glowplug and start the engine.
4.When re-starting the engine, turn the flywheel by
hand, as before (but without removing the glow-
plug) to make sure that there is nothing unusual,
before energising the glowplug and applying the
starter.
Warning!
Do not attempt to turn the engine with the starter
if the engine is over-primed (flooded) with fuel.
To do so is likely to seriously damage the engine.
CARE AND MAINTENANCE
1.
2.
3.
The minute particles of foreign matter, that are
present in any fuel may, by accumulating and
partially obstructing fuel flow, cause engine
performance to become erratic and unreliable.
O.S. 'Super-Filters' (large and small) are available,
as optional extras, to deal with this problem.
One of these filters, installed the outlet tube inside
your refueling container, will prevent the entry of
foreign material into the fuel tank. It is also
recommended that a good in-line filter be installed
between the tank and carburetor.
Do not forget to clean the filters regularly to remove
dirt and lint that accumulate on the filter screens.
Also, clean the carburetor itself occasionally.
At the end of each operating session, drain out any
fuel that may remain in the fuel tank.
Afterwards,energize the glow-plug and try to restart
the engine, to burn off any fuel that may remain