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

18
ENGINE INSTALLATION
Make sure that the engine mounting beams in
the hull are parallel, with their top surfaces in
the same plane. If they are not, the engine will
not rest firmly as the engine mounting faces
(undersides of the mounting lugs) are precision
machined to be flat and in the same plane.
Poor installation may not only cause vibration,
erratic running and loss of performance, but
may also damage the engine itself by
deforming the crankcase, cylinder, etc.
The mounting beams and adjacent hull
structure should be as rigid as possible so that
the engine may develop its full performance.
Use 3mm steel screws, such as Allen socket-
head type, with locknuts, for bolting the engine
to the mounting beams. 1.
2.
3.
Touches here
Chamfer edges
Touches here
File off
Before installing the engine in the model, clean out the
engine compartment. If any remaining sand paper and
glass wool residues are not removed completely, they
may be sucked into the engine and damage the engine.
Screws are prone to loosen during running.
Be sure to use the Lock Washers available as
optional extra or locking glue to prevent their
loosening. 4.
If the holes in the mounting beams do not align
exactly with the engine's mounting lugs,
enlarge them slightly with a needle file so that
the mounting screws pass through the holes
smoothly without being forced.
19
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.
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)
The somewhat violent changes of hull attitude
that occur in running, combined with the fact
that, in boats 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.