Fuel Pump; Replacing The Mechanical Pump; Fuel Pump - Replacement; Replacing The Pulse Fuel Pump - Kohler CH18-745 Service Manual

Kohler Engine Parts Call K&T 606-678-9623 or 606-561-4983

Fuel Pump

General
These engines are equipped with either a pulse or
mechanical fuel pump. See Figures 5-1 and 5-2. The
pumping action is created by either the oscillation of
positive and negative pressures within the crankcase
through a hose, or by direct lever/pump actuation off
rocker arm movement. The pumping action causes the
diaphragm on the inside of the pump to pull fuel in on
its downward stroke and to push it into the carburetor
on its upward stroke. Internal check valves prevent
fuel from going backward through the pump.
Outlet Line (to Carburetor)
Pulse Line
Figure 5-1. Pulse Style Fuel Pump.
Performance
Minimum fuel delivery rate must be 7.5 L/hr. (2 gal./hr.)
with a pressure at 0.3 psi and a fuel lift of 18 in. from
carburetor inlet. A 1.3 L/hr. (0.34 gal./hr.) fuel rate must
be maintained at 5 Hz.

Fuel Pump - Replacement

Replacing the Pulse Fuel Pump

Replacement pumps are available through your source
of supply. To replace the pulse pump follow these
steps.
1. Disconnect the fuel lines from the inlet and outlet
fittings.
2. Remove the hex. flange screws securing the fuel
pump.
3. Remove the pulse line that connects the pump to
the crankcase or valve cover.
4. Install the new fuel pump using the hex. flange
5. Connect the pulse line to the pulse fitting.
6. Connect the fuel lines to the inlet and outlet
Pulse Fuel
Pump

Replacing the Mechanical Pump

The mechanical pump is an integral part of the valve
cover assembly and not serviced separately. See
Figure 5-2.
1. Disconnect the fuel lines from the inlet and outlet
Inlet Line
2. Follow the procedure for replacing the valve cover
3. Reconnect the fuel lines to the inlet and outlet
Figure 5-2. Mechanical Fuel Pump.
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Fuel System and Governor
NOTE: On most models, the pulse line is
connected to a fitting on the crankcase,
while on early models, it is connected to
the valve cover.
screws. Torque the hex. flange screws to 2.3 N·m
(20 in. lb.).
NOTE: Make sure the orientation of the new
pump is consistent with the removed
pump. Internal damage may occur if
installed incorrectly.
fittings.
fittings.
(Sections 9 and 11).
fittings.
Section 5
5
Outlet Line (to
Carburetor)
Mechanical
Fuel Pump
Inlet Line
5.3