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Fuel System
20 690 01 Rev. F KohlerEngines.com
Typical carbureted fuel system and related components
include:
● Fuel tank.
● Fuel lines.
● In-line fuel fi lter.
● Fuel pump.
● Carburetor.
Fuel from tank is moved through in-line fi lter and fuel
lines by fuel pump. Fuel then enters carburetor fl oat bowl
and 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 PUMP
Some engines are equipped with one of two optional
pulse fuel pumps. One is mounted to speed control
bracket, and other is mounted to air cleaner base.
Fuel pump has two internal chambers separated by
a diaphragm. Air chamber is connected to engine
crankcase by a rubber hose. Fuel chamber has an inlet
from fuel tank, and an outlet to carburetor. Inlet and
outlet each have an internal, one-way check valve.
Alternating negative and positive pressures in crankcase
activate pump. When piston moves upward in cylinder,
negative pressure (vacuum) is created in crankcase
and in air chamber of pump. Diaphragm fl exes toward
negative pressure, and suction draws fuel past inlet
check valve, into fuel chamber. Downward movement
of piston causes a positive pressure in crankcase and
air chamber, pushing diaphragm in opposite direction,
putting pressure on fuel. Inlet check valve has now
closed, so fuel is forced past outlet check valve, to
carburetor.
Repair
Pulse fuel pumps are not serviceable and must be
replaced when faulty.
Removal
Speed Control Bracket Mounted Fuel Pump
1. Disconnect inlet, outlet, and pulse lines from fuel
pump. Mark lines for proper reassembly.
2. Remove screws attaching fuel pump.
Air Cleaner Base Mounted Fuel Pump
1. Remove dipstick and blower housing.
2. Disconnect inlet, outlet, and pulse lines from fuel
pump. Mark lines for proper reassembly.
3. Remove fuel pump from bracket.
Installation
Speed Control Bracket Mounted Fuel Pump
1. Install new fuel pump, and secure with hex fl ange
screws. Torque screws to 5.9 N·m (52 in. lb.). Do not
over tighten.
2. Connect inlet, outlet, and pulse lines to their
respective fi ttings on pump. Secure with clamps.
Air Cleaner Base Mounted Fuel Pump
1. Install new fuel pump, pressing fuel pump onto
bracket past locking tabs.
2. Connect inlet, outlet, and pulse lines to their
respective fi ttings on pump. Secure with clamps.