Wacker Neuson WM 80 User Manual

WM 80 Repair Carburetor Basics
wc_tx000522gb.fm 47
5.2 Walbro Carburetor Operation
Fuel Pump
The fuel pump is made up of a diaphragm (a) and a series of check
valves (b & c). The power to operate the fuel pump comes from the
crankcase impulse.
As the engine’s piston moves up into the cylinder it creates a low-
pressure area in the crankcase. The vacuum pulse travels through the
impulse passage and draws up on the pump diaphragm creating a
vacuum within the fuel chamber. Atmosphere pressure in the fuel tank
pushes the fuel through the fuel filter and fuel line. The vacuum opens
the inlet check valve (b) and allows fuel to fill the fuel chamber. The
vacuum also closes the outlet check valve (c).
As the piston moves down into the crankcase it pressurizes the air.
The pressurized air travels through the impulse passage into the
carburetor fuel pump. It pushes on the diaphragm pressurizing the fuel.
The pressurized fuel closes inlet check valve opens the outlet check
valve. Fuel flows to the inlet screen and to the inlet needle and the fuel
metering system.

Wacker Neuson WM 80 Specifications

General

Brand	Wacker Neuson
Model	WM 80
Category	Engine
Language	English