Kohler Command PRO CH750 [23/92] Fuel system

Typical carbureted fuel system and related components

include:

● Fuel tank and valve.

● 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

Low permeation fuel line must be installed on carbureted

Kohler Co. engines to maintain EPA and CARB

regulatory compliance.

FUEL PUMP

These engines use either a mechanical pump or 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

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.

Fuel Pump Replacement

Pulse Fuel Pump

NOTE: On most models, pulse line is connected to a

fi tting on crankcase, while on early models, it is

connected to valve cover.

NOTE: Make sure orientation of new pump is consistent

with removed pump. Internal damage may occur

3. Connect pulse line to new fuel pump and make sure

opposite end is properly connected to fi tting on

crankcase or valve cover.

4. Attach new fuel pump using screws. Torque screws

to 2.3 N·m (20 in. lb.).

5. Reconnect fuel lines to inlet and outlet fi ttings and

secure with clamps.

Mechanical Pump

Mechanical fuel pump is an integral part of valve cover

assembly and not serviced separately.

FUEL SYSTEM TESTS

When engine starts hard or turns over but will not start, fuel system might be causing problems. Test fuel system by

performing following test.

1. Check for fuel in combustion chamber.

a. Disconnect and ground spark plug leads.

b. Close choke on carburetor.

c. Crank engine several times.

d. Remove spark plug and check for fuel at tip.

2. Check for fuel fl ow from tank to fuel pump.

a. Remove fuel line from inlet fi tting of fuel pump.

b. Hold line below bottom of tank. Open shut-off

valve (if equipped) and observe fl ow.

Fuel fl ows from fuel line. Check for faulty fuel pump (step 3).

If fuel pump is working, check for faulty carburetor. Refer

to Carburetor.

No fuel fl ow from fuel line. Check fuel tank cap vent, fuel pickup screen, in-line

fi lter, shut-off valve, and fuel line. Correct any observed

problem and reconnect line.

Fuel line condition. Check for a clogged fuel line. If fuel line is unobstructed,

check for overfi lled crankcase and/or oil in pulse line. If

checks don't reveal cause of problem, replace pump.

Fuel System