O.S. Engines 21VZ-M User Manual

Page 11

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20

Open the Needle-Valve 1.5 turns from the
fully closed position.

Open

Close

Needle Valve

Swith on the transmitter and make sure that
each linkage moves correctly.

Turn the engine with an electric starter or
recoil starter to draw fuel into the engine.

Fuel

Deliver fuel into the carburetor.

Fuel tank side

Throttle Trim

Raise the throttle trim 2 or 3 clicks on the
transmitter for easier starting.

Now connect glowplug battery lead to heat
the plug filament and start the engine.

Start the engine using an electric starter
making sure the engine rotation direction is
correct (counter-clockwise seen from the
crankshaft end).

When the engine starts, first repeat low
speed running and medium speed running
by raising and lowering throttle stick on the
transmitter to warm up the engine.
Aviod high speed running.

21

PRECAUTIONS
When starting the engine, with the hull out
off the water and no load on the engine,
even below half throttle, the engine can
over-rev. Prolonged running at higher
throttle settings can result in seizure of the
connecting rod and crankpin. Never run the
engine with the throttle above the starting
setting with the hull out of the water and no
load on the engine.

Next, disconnect the glowplug battery and
try running the hull on the water. If the
engine stalls, open the throttle fractionally,
but try to keep the engine running as rich as
possible: if it stops because of being
excessively over-rich, close the Needle-
Valve 30˚ and try again.

Run the hull on the water until one tank of fuel
has been consumed, then close the Needle-
Valve 30˚ and run the hull for another full tank
of fuel. Repeat this procedure until 5 more
tanks of fuel have been consumed, during
which time the throttle may be opened for brief
bursts of increased power.
If the engine stops at medium speeds, close
the Mixture Screw 10˚.

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