Kohler Courage SV710-740 Service Manual page 35

On engines equipped with a pulse type fuel pump, the
pumping action is created by the oscillation of positive
and negative pressures within the crankcase. This
pressure is transmitted to the pulse pump through
a rubber hose connected between the pump and
crankcase. 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. Two check valves prevent fuel from
going backward through the pump.
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 24 in. A 1.3 L/hr. (0.34 gal./hr.) fuel rate must be
maintained at 5 Hz.
Replacement pumps are available through your
source of supply. To replace the pulse pump follow
these steps. Note the orientation of the pump before
removing.
1. Disconnect the fuel lines from the inlet, outlet
and pulse fittings on fuel pump.
2. Remove the two mounting screws and take off
the pump.
3 Connect the pulse line to the new fuel pump and
make sure opposite end is properly connected
into valve cover.
NOTE: Make sure the orientation of the new
pump is consistent with the removed
pump. Internal damage may occur if
installed incorrectly.
4. Attach the new fuel pump using the hex flange
screws. Torque the screws to 2.3 N·m (20 in. lb.).
5. Connect the fuel lines to the inlet and outlet
fittings and secure with the clamps.
Engines in this series are equipped with either a
Keihin or Nikki fixed main jet carburetor. Most
carburetors utilize a fuel shut-off solenoid and feature
a self-relieving choke. These carburetors include three
main circuits, which function as follows.
Float Circuit: The fuel level in the bowl is maintained
by the float and fuel inlet needle. The buoyant force
of the float stops fuel flow when the engine is at rest.
When fuel is being consumed, the float will drop and
fuel pressure will push the inlet needle away from
the seat, allowing more fuel to enter the bowl. When
demand ceases, the buoyant force of the float will
again overcome the fuel pressure and stop the flow.