Wacker Neuson WM 80 User Manual

WM 80 Repair Carburetor Basics
wc_tx000522gb.fm 55
5.4 Tillotson Carburetor Operation
See Graphic: wc_gr002891
Fuel Pump:
The Tillotson carburetor uses a flexible diaphragm fuel pump (a) to
operate an inlet valve (b) which controls fuel flow to the carburetor fuel
reservoir (c). The fuel pump operates by reacting to pressure changes
in the engine crankcase transmitted through an impulse line (d). The
impulse line can be external (connected to the crankcase through a
plastic tube), or internal to the carburetor (connected through an orifice
drilled in the carburetor adapter) depending on carburetor version.
During the compression stroke, the vacuum created in the crankcase
is transmitted to the carburetor through the impulse line. The vacuum
pulls the fuel pump diaphragm upward. The upward movement of the
diaphragm creates a vacuum in the fuel reservoir which opens the fuel
inlet valve and draws fuel into the fuel reservoir. During the engine’s
power stroke, positive crankcase pressure, also transmitted through
the impulse line, pushes the diaphragm down. The downward
movement of the diaphragm closes the inlet valve and forces fuel
toward the inlet needle valve (e).
a
d
c
b
wc_gr002891
e

Wacker Neuson WM 80 Specifications

General

Brand	Wacker Neuson
Model	WM 80
Category	Engine
Language	English