Service Manual

3-2
Table of Contents
Twin Cylinder Engine Service Manual
February 2017 - Digital Edition
TWO BARREL CARBURETOR AND FUEL SYSTEM
This section covers the description, location, and operation of the fuel system including the two-barrel carburetor,
cast aluminum intake manifold, fuel lines, fuel lter, and fuel pump.
WARNING: Unauthorized adjustment to the carburetor or fuel system may make the machine non-
compliant to EPA standards. Verify components are set to factory standards.
WARNING
Explosive fuel can cause res and severe burns.
Do not ll fuel tank while engine is hot or running.
Gasoline is extremely ammable and its vapors can
explode if ignited. Store gasoline only in approved
containers, in well ventilated, occupied buildings, away
from sparks or ames. Spilled fuel could ignite if it
comes in contact with hot parts or sparks from ignition.
Never use gasoline as a cleaning agent.
Fuel System
Introduction: The fuel system consists of a sealed gas tank with venting into the air lter intake manifold, a
vacuum powered fuel pump, a two-barrel carburetor with a vacuum override choke system and a cast aluminum
intake manifold mounted to the top of each cylinder head.
Operation
Fuel Flow: The fuel ows from the fuel tank through the fuel lter, to the fuel pump and continues to the top of the
carburetor. When the carburetor oat drops, the needle opens and the fuel ows into the bowl until the oat rises
and closes the needle. Air moving through each venturi creates a low pressure. Atmospheric pressure pushing
down on the fuel in the carburetor bowl pushes fuel up the nozzles and into the air stream. The air stream, mixed
with fuel droplets, continues through the intake pipe into the combustion chamber (Figure 1).
Figure 1
A. Intake Manifold
B. Fuel Filter
C. Fuel Line
D. Vacuum Line
E. Fuel Pump
F. Fuel Line
G. Carburetor
A
B
C
D
E
F
G