O.S. Engines 21RZ-R (P) - Manual (Page 18)

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.
4.
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 to 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
Then, inject some after-run oil into the engine, and
rotate the engine with an electric starter for 4 to 5
seconds to distribute the oil to all the working
parts.
inside the engine. Repeat this procedure until the
engine fails to fire. Do this while the engine is still
warm.
Note:
5.
Do not inject after-run oil into the carburetor as
this may cause the O-rings inside the carburetor
to deteriorate. These procedures will reduce the
risks of starting difficulties or corrosion after a
period of storage.
Finally, when cleaning the exterior of the engine,
use methanol or kerosene. Do not use gasoline or
any solvent that might damage the silicone fuel
tubing.
Caution:
The rear crankshaft bearing of this engine uses a
special plastic retainer. If the front housing needs
to be heated to remove or replace the bearing, do
not allow the bearing to exceed 120˚C (248˚F),
otherwise it may be damaged and rendered
unserviceable.
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