Kohler LH630-775 Service Manual page 30

Mechanical Fuel Pump
The mechanical fuel pump is built into the #2 valve
cover. The actuating arm of the pump extends down
inside the cover and contacts one of the rocker arms.
Downward movement of the rocker arm allows the
pump diaphragm to flex down, drawing in fuel. As
the rocker arm comes up, the fuel is forced out toward
the carburetor.
Pulse Fuel Pump
Mechanical Fuel Pump
Figure 5-1. Fuel Pump Styles.
Replacing The Fuel Pump
Replacement pumps are available through your source
of supply. To replace the pulse pump follow these
steps. Note the orientation of pump before removing.
Pulse Fuel Pump
1. Disconnect the fuel lines from the inlet and outlet
fittings.
2. Remove the hex flange screws mounting fuel
pump to support.
Fuel System and Governor
3. Remove the vacuum line that connects the pump
to the crankcase.
4. Install a new pump using the hex flange screws.
NOTE: Make sure the orientation of the new
pump is consistent with the removed
pump. Internal damage may occur if
installed incorrectly.
5. Connect vacuum line between the pump and
crankcase.
6. Tighten the hex flange screws to 2.3 N·m
(20 in. lb.).
7. Connect the fuel lines to the inlet and outlet
fittings.
Mechanical Fuel Pump
1. Disconnect the fuel lines from the inlet and outlet
fittings.
2. Clean the area and remove the four screws
securing the valve cover/pump assembly to the
cylinder head. Loosen (but do not remove) the
four valve cover screws on the opposite side.
3. Lift the air cleaner mounting bracket up slightly
and remove the valve cover/pump assembly.
Remove and discard the old gasket.
4. Rotate the engine by hand while observing the
actuating rocker arm. Stop rotating when end of
the rocker arm is at the lowest point (spring is at
maximum compression, and valve is open).
5. Position the new gasket onto the new cover/fuel
pump assembly and install onto cylinder head.
Align the air cleaner mounting bracket holes with
the upper two valve cover screw holes.
6. Install the longer screws in the upper holes
and the shorter screws in the lower holes.
Finger tighten all eight valve cover mounting
screws (four each side), then torque the screws
to 6.2 N·m (55 in. lb.) in the sequence shown in
Figure 5-2.
Section 5
5
5.3