O.S. Engines PA-104 Carb - 72504000 - Manual (Page 2)

FUEL TANK
If the fitting of the "klunk" type fuel pick-up weight in the fuel
tank is incorrect, the weight may stick to the tank wall, resulting
in an irregular fuel flow to the carburettor, or, alternatively, in
the fuel flow being cut off during the course of sharp acrobatic
manoeuvres. Therefore, it is advisable to make slots in the end of
the weight, with a file or hacksaw blade, as shown in Fig. 10.
Thoroughly wash out the weight to remove any minute particles
of metal before reinstalling it in the tank.
Fig. 9 Fig. 10
Use thick silicone tubing.
10-15mm
(3/8-5/8")
STARTING THE ENGINE
1. Fill the fuel tank.
2. From its fully closed position, open the needle-valve approxi-
mately 1 to 1-1/4 turns (when the standard O.S. 873 silencer
is used), or 1-1/2 to 2 turns (when a tuned silencer is used).
3. Open the throttle fully.
4. Placing your finger over the carburettor to choke the intake,
turn the propeller by hand until fuel is pumped as far as the
carburettor.
5. When fuel is seen to reach the carburettor, remove your finger
from the intake immediately.
6. Close the throttle to the idling position and turn the propeller
through two extra revolutions to prime the engine. DO NOT
turn the prop more than this, or the engine will be over-primed.
7. Connect the battery to the glowplug and start the engine.
Note:
If the engine is over-primed (i.e. flooded), pinch the fuel
delivery tube (Tube B) with a suitable clip or clamp before
attempting to start the engine. If the engine remains over-
primed and unwilling to start, close the needle-valve com-
pletely, remove the glowplug and flip the propeller briskly
to eject excess fuel from the cylinder via the glowplug hole.
8. Check that sufficient fuel can reach the engine to cause it to
run rich (for running-in purposes, etc.) when the needle-valve
is more than 3 turns open. If the engine cannot be made to run
rich, check as follows:
* Make sure that the fuel filter or carburettor is not partially
obstructed with foreign matter.
* Make sure that there are no holes in the piping or air bubbles
in the fuel flow.
* Make sure that the fuel does not "froth" in the tank when
the engine is running. This can occur if the tank is not
properly insulated from vibration.
* Make sure that the fuel pick-up weight is not being partially
obstructed by contact with the tank wall. (Refer to previous
instructions under "FUEL TANK".)
In the unlikely event that the engine cannot be persuaded
to run rich, after checking the above, it is possible that a
fault has developed in the pump. In this case, consult the
O.S. engine distributor in your country.
Coution:
In the throttle is 'blipped' rapidly and repeatedly between
the idling and medium speed positions during (for example)
taxying, an excess of fuel will be pumped into the engine.
The engine may then refuse to pick up speed, even when
the throttle is opened fully, and may stop. The throttle
lever should be opened gradually to match the engine's
natural acceleration under load. The recommended pre
take-off check is to fully open the throttle, once, with the
aircraft under restraint. The throttle is then returned to the
idling position, before being smoothly advanced for the
take-off run.
Time
Fi».11
Time
ADJUSTMENTS
Adjustment of the PA-104 System is confined to the Type 46
carburettor. No adjustments to the pump are called for. Carbu-
rettor adjustment broadly follows the procedure for setting up
a conventional suction-feed system. See separate instruction leaflet
for O.S. Type 46 carburettor.
MAINTENANCE
If, after use, the fuel system is left unattended for a lengthy period,
there will be a tendency for the methanol content of the fuel to
evaporate sufficiently for the oil content to "gum" the internal
parts of the pump. Therefore, it is advisable, at the end of the
day's flying, to empty the fuel tank, invert the engine, and pump
out the remaining fuel in the system by rotating the propeller
until no more fuel is ejected from the carburettor.
If the pump is not in use for a while (more than one month),
remove the pump and wash out its interior by injecting methanol
or kerosene through the "IN" nipple. Fit the sealing caps (provid-
ed) to the nipples, after draining out the methanol or kerosene.
Note:
If you use kerosene, take care not to allow this to come into
contact with the fuel tubing, otherwise the tubing will swell
and deteriorate.
© Copyright 1990 by O.S. Engines Mfg. Co., Ltd. All rights reserved. Printed in Japan
O.S.PUMP SYSTEM
Distributed in the United
States by permission of
Perry Aeromotive. Inc. under
U.S. Patent No. 3,96 7,606.
6-15 3-chome Imagawa Higashisumiyoshi-ku
Osaka 546, Japan. TEL. (06) 702-0225
FAX. (06) 704-2722