Manual

Fyr Pak
Operation and Maintenance Manual
8
The FYR PAK pumping unit consists of 6 major subassemblies; the engine, pump, priming system, mounting
base, overspeed control switch and backpack frame.
ENGINE
The lightweight engine is a single cylinder, two cycle, air-cooled version producing 8 hp (6 kW) from its
8.2 cu. inch (134 cc) displacement using a gasoline/oil fuel mixture. The engine is equipped with water resistant
solid state ignition, a pressure carburetor with built-in fuel pump, and an on/off ignition toggle switch.
The engine’s interior is protected from impurities by the use of a wire mesh element air ler, a 75 micron in-line
fuel ller, and an integral fuel strainer built into the fuel pump.
PUMP
The engine crankshaft extension serves as the pump shaft with an enclosed type bronze impeller mounted
directly on the shaft. The shaft is protected against corrosion by a bronze sleeve, an “O”-ring, and a mechanical
type, self-lubricating and adjusting seal. The impeller is hydraulically sealed by a replaceable, patented oating,
bronze clearance ring located in the suction of the aluminum volute body. The volute body is attached
to the cast aluminum pump head by four mounting scr
ews.
The pump head serves as the mounting bracket for the pump/engine assembly. It is attached to the mounting
base with rubber vibration shock mounts. It also incorporates a handle for positioning the unit of carrying short
distances.
PRIMING SYSTEM
The priming pump is a hand operated piston pump. Its purpose is to remove air from the pump allowing
atmospheric pressure to push water through the inlet hose into the pump. A priming valve is included which
controls air ow through the priming line.
MOUNTING BASE
The mounting base is an intermediate part to which the engine is attached with three shock vibration isolation
mounts. The base is attached to the backpack frame with four vinyl clad tubing clamps. The mounting base has
the overspeed control switch, priming pump mounting clamps and Hale nameplate attached to it.
OVERSPEED CONTROL
The overspeed switch control assembly is an added safeguard against overspeeding of the engine. The
overspeed switch is attached to the mounting base of the pumping unit below the carburetor. Attached to the front
of the overspeed switch is a exible transparent hose that is connected to the nozzle plate (riveted to the engine
fan housing). Connected to the back of the overspeed switch are two wires one goes to the engine’s ignition coil,
the other goes to ground (engine). The switch senses the air pressure generated by the engine’s cooling fan.
When the engine reaches a speed in excess of that which would normally occur the fan air pressure generated
will be sufcient to cause the switch to close thereby grounding the solid state ignition. The engine speed will
then decrease until the air pressure reaches a lower trip point, reactivating the ignition system and the engine will
accelerate. The engine will decelerate and accelerate alternately until the operating conditions are returned to
their normal mode.
BACKPACK FRAME
The backpack frame serves as a convenient means for transporting the FYR PAK unit over long distances. The
backpack frame is of conventional design incorporating adjustable shoulder straps and hip belt. The addition of