Fuel System - Kohler HD Series Service Manual

Typical carbureted fuel system and related components
include:
● Fuel tank.
● Fuel lines.
● In-line fuel fi lter (if equipped).
● In-nipple fuel fi lter (if equipped).
● Fuel shut-off valve (if equipped).
● Carburetor.
● Fuel pump (if equipped) and second in-nipple fuel fi lter
after tee fi tting.
Fuel tank outlet is located above carburetor inlet,
allowing gravity to feed fuel through in-line fi lter and fuel
line to carburetor.
Engines equipped with a pulse fuel pump allows for
complete fuel usage. Engines operated at extreme
cylinder head up angles of operation restrict complete
fuel tank volume usage in gravity feed mode due to
angle of engine. Addition of pulse pump aids in drawing
and delivering full tank of fuel to carburetor.
Fuel enters carburetor through fuel shut-off valve (if
equipped) and then goes to carburetor fl oat bowl. Fuel
is drawn into carburetor body and mixed with air. This
fuel-air mixture is then burned in engine combustion
chamber.
FUEL RECOMMENDATIONS
Refer to Maintenance.
FUEL LINE
Low permeation fuel line must be installed on carbureted
Kohler Co. engines to maintain EPA and CARB
regulatory compliance.
FUEL SHUT-OFF (if equipped)
Some engines are equipped with a fuel shut-off located
at carburetor. It controls fuel fl ow from tank to carburetor.
FUEL PUMP (if equipped)
H
F
G
B
E
First In-Nipple Fuel
A
Filter
14 690 10 Rev. --
E
F
B
E
D
C
B Inlet
KohlerEngines.com
C Tee Fitting
E Pulse
G Fuel Pump Bracket
Some engines use a pulse style fuel pump. Pumping
action of pulse style pumps is created by oscillation of
positive and negative pressures within crankcase. This
pressure is transmitted to pulse pump through rubber
hose connected between pump and crankcase. Pumping
action causes diaphragm on inside of pump to pull fuel
in on its downward stroke and to push it into carburetor
on its upward stroke. Two check valves prevent fuel from
going backward through pump.
Repair
Pulse fuel pumps are not serviceable and must be
replaced when faulty.
Fuel Pump Replacement
NOTE: Make sure orientation of new pump is consistent
with removed pump. Internal damage may occur
if installed incorrectly.
To replace pulse fuel pump follow these steps. Note
orientation of pump before removing.
1. Disconnect fuel lines from inlet, outlet, and pulse
fi ttings on fuel pump.
2. Inspect both in-nipple fuel fi lters (located at fuel tank
outlet fi tting and tee fi tting) for dirt/debris. Clean/
replace as required.
3. Remove screws securing fuel pump to bracket and
take off pump.
4. Connect pulse line to new fuel pump and make sure
opposite end is properly connected to fi tting in valve
cover.
5. Secure new fuel pump to bracket using screws.
Torque screws to 2.3 N·m (20 in. lb.).
6. Connect fuel lines to inlet and outlet fi ttings and
secure with clamps.
A

Fuel System

Second In-Nipple
D
Fuel Filter
F Outlet
H Fuel Pump
21