O.S. Engines FS-91S II (P) - Manual (Page 10)

A B
D C
Make sure there is adequate ventilation.
<
FS-91S 2 -P
>
The function of the various tubes connected to the engine and
tank (see sketch) are as follows:
For Pipe A (tank to pump) use similar heavy-duty silicone-
rubber tubing of approximately 2.5mm bore and 5.0mm
outside diameter.
To draw fuel from tank to pump nipple marked 'IN'.
To deliver fuel from pump nipple marked 'OUT' to
carburettor.
To connect crankcase breather nipple (behind
camshaft housing) to intake pipe.
To deliver crankcase pressure pulses to pump dia-
phragm.
Pipe A:
Pipe B:
Pipe C:
Pipe D:
Note: Since the FS-91S 2 -P has a positively pumped fuel
supply, it does NOT require muffler pressurization.
Pipes B, C and D are already installed when the engine is
shipped from the factory. If any of these pipes should
need to be replaced, due to damage or installation
problems, be sure to use tubing of the same dimensions
and quality as the originals.
CARE OF FUEL PUMP & REGULATOR
A short preliminary period of part-throttle running is required
to ensure that the pump system functions correctly during the
running-in process. Set the throttle 75% open from the fully-
closed position and run the engine for 2-3 minutes. This will
ensure that the engine becomes rich enough when the
needle-valve is opened at full throttle during running-in.
Important
<
FS-91S 2 -P
>
9