Os-engines PA-104 Carb - 72504000 Bedienungsanleitung PDF herunterladen

INSTRUCTIONS FOR O.S. PA-104 PUMP SYSTEM

The O.S. PA-104 Pump System consists of the unique O.S. Type PD-04 diaphragm fuel pump and matching large-throat

carburettor (O.S. Type 46), and has been developed specifically for O.S. MAX-40SF, 46SF, 40VF and 46VF engines.

The O.S. Pump System provides more power and ensures that fuel is delivered to the carburettor at the pressure reguired to

maintain the optimum mixture strength, irrespective of fuel tank location or aircraft attitude.

Note: This pump system cannot be fitted to the O.S. MAX-40FSR or 45FSR since the Type 46 carburettor cannot be installed in these engines.

PRINCIPLE OF THE DIAPHRAGM PUMP

Diaphragm

(oscillates as the pressure in the crankcase varies.)

Negative and positive pressures occur in these

chambers in accordance with upward and down-

ward strokes of engine's piston.

Fig.1

Check Valve No.1. Negative pressure causes Check Valve 1to open and admit fuel from

tank to pump. Valve automatically closes under positive pressure to prevent reverse

flow.

Under negative pressure

Under positive pressure

Check Valve No 2 Positive pressure opens Check Valve 2 and delivers fuel to carburettor.

Valve automatically closes under negative pressure to prevent reverse flow

Fig.

Figs 1 & 2 are merely diagrammatic to explain the principle of the

diaphragm pump. Actual construction is more complicated.

INSTALLATION OF PRESSURE NIPPLE AND CARBURETTOR

* Remove the crankcase cover-plate (backplate) from the engine.

Drill and tap cover-plate boss with M3.5x0.6 Metric thread and

fit nipple supplied.

Important! After tapping, be sure to wash out screw hole

thoroughly with kerosine.

Note:

For this modification, an M3.5 tap set, including a 2.9mm

drill for the pilot hole, is available as an optional extra

(Code No. 27901002). Alternatively, for owners who do

not care to do this work, a replacement cover-plate, complete

with nipple installed, is also obtainable (Code No.25407001).

* Refit cover-plate and install the O.S. Type 46 carburettor.

Make a pilot hole with

2.9mm drill.

Cut thread at least 5mm (3/16") deep

Nipple supplied

Fig.

PIPING

* For piping, use heavy duty silicone fuel tubing of approximately

2.5mm bore and 5mm outer diameter.

* A feature of the O.S. Pump System is that the fuel tank does

not have to be placed close behind the engine, but tube lengths

should be kept as short as possible. Take care not to cause any

kinks in the "plumbing".

IN (Tube A)

P (Tube C)

Make sure that the length

of Tube C is less than

10cm

in.).

Fig.

TubeA

TubeB

Overflow

(Do not seal off)

Type 46 carburettor

PD-04

Fig.

Tube A: To draw fuel from the fuel tank to the pump.

Tube B : To deliver fuel from the pump to the carburettor.

Tube C: To deliver the crankcase pressure pulse to the pump.

INSTALLATION

Here are examples of typical installations. (Figs 6 & 7)

* The ideal location for the pump is one in which the center

of the pump is on the same level as the axis of the carburettor

barrel as shown in Fig. 6. In many cases, this cannot be achiev-

ed, precisely, within the existing structure of the airframe.

However, try to fit the pump as closely as possible to this

optimum location. If the pump is installed more than 5cm

(2 in) above or below the ideal position, there may be a slight

variation in fuel/air mixture strength between level and inverted

flight.

Type 46 carburettor

Carburettor center line

Fig.

PD-04 pump

Fix the pump on the firewall, front bulkhead, or side of the

engine compartment with 3mm self-tapping screws. It is advis-

able to insert a piece of sheet rubber between the pump and

mounting surface. DO NOT attach the pump directly to any

part of the engine.

If it is not possible to mount the pump as described, it may

be possible to wrap it in foam rubber and insert it into a con-

venient space in the engine compartment, but make sure that

it does not touch the engine itself.

Caution:

When installing the pump, take care that the vent hole in

the pump body is not obstructed.

Do not ill the tank from here,

or the pump may be damaged.

Disconnect here when

filling the tank.

It may be convenient to lead the pipes

outside the fuselage and connect with

approx. 40~50mm(l-1/2~2") length

of silicone tubing.

Fig.

Do not block or seal.

Fig.

Overflow

L-shaped nipple or aluminum

tubing.

Connect to the nipple

of the cover plate.

Silicone tubing

WARNINGS

* Do not dissassemble the pump

Never take the pump unit apart. Once the pump has been

dismantled, its original performance may not be restored when

it is reassembled.

* Do not insert anything into the nipples

Inserting a pin, etc., into the nipples and/or air vent hole is

likely to damage the pump and render it inoperative.

* Use fuel filters

Any foreign matter entering the Pump System may interfere

with its correct functioning and may even damage the pump

diaphragm. Be sure to filter, all fuel before filling the tank and,

most important, use a good quality fine filter in the delivery

tube between the tank and pump.

Fuel tank

Pump incorporates a regulator here

to maintain fuel outlet pressure at a

constant level.

1 2

Inhaltsverzeichnis

Seite 1

INSTRUCTIONS FOR O.S. PA-104 PUMP SYSTEMThe O.S. PA-104 Pump System consists of the unique O.S. Type PD-04 diaphragm fuel pump and matching large-thro

Seite 2 - U.S. Patent No. 3,96 7,606

FUEL TANKIf the fitting of the "klunk" type fuel pick-up weight in the fueltank is incorrect, the weight may stick to the tank wall, resulti

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