8
〈FS-70SⅡ, FS-91SⅡ〉
NEEDLE-VALVE EXTENSION
The needle-valve supplied with this engine is designed to
accept an extension so that, when the engine is enclosed in a
cowling, the needle-valve may be adjusted from the outside.
An L-shaped rod, of appropriate length, may be inserted in the
needle-valve knob center hole and secured by tightening the
set-screw with a 1.5mm Allen key.
THROTTLE LINKAGE
Before connecting the throttle to its servo, make sure that the
throttle arm and linkage safely clear any adjacent part of the
airframe structure, etc., as the throttle is opened and closed.
Connect the linkage so that the throttle is fully closed when
the transmitter throttle stick and its trim lever are at their
lowest settings and fully open when the throttle stick is in its
fully-open position..
Carefully align the appropriate holes in the throttle arm and
servo horn so that they move symmetrically and smoothly
through their full travel.
Install these in the following sequence.
Screw the header pipe into the cylinder head until it " bottoms
", then unscrew sufficiently to achieve the desired exhaust
angle and tighten the locknut securely with a 14mm wrench.
Screw the silencer onto the outer end of the header pipe and
tighten the other locknut.
The application of a heatproof silicone sealant to the threads of
the exhaust system is recommended to reduce the risk of joints
loosening and the leakage of exhaust gases and oil residue.
EXHAUST HEADER PIPE & SILENCER
Reminder:
Model engines generate considerable heat and contact with
the header pipe or silencer may result in a serious burn.
If you need to tighten the silencer joints, which may loosen
when they are hot, use a thick folded cloth for protection.
FUEL LINES
For fuel line, use, heavy-duty silicone-rubber tubing of
approximately 2.5mm inside and 5.0mm outside diameter.
Note: Be sure to use a muffler-pressurized fuel feed
system.
It is advisable to fasten connections with tubing clips or secure
binding.
9
A B
D
C
Make sure the tank vent is not obstructed.
The function of the various tubing connected to the engine
and tank (see sketch) are as follows:
For Line 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.
Line A:
Line B:
Line C:
Line D:
Note: Since the FS-91S -P has a positively pumped fuel
supply, it does NOT require muffler pressurization.
Lines B, C and D are already installed when the engine is
shipped from the factory. If any of these lines 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
