Fuel System Typical carbureted fuel system and related components include following: ● Fuel tank. ● In-line fuel fi lter. ● Fuel pump. ● Carburetor. ● Fuel lines. FUEL PUMP These engines use either a mechanical fuel pump, or optional remote-mounted electric fuel pump assembly. Operation of mechanical fuel pump occurs by direct lever/pump actuation off rocker arm movement. Pumping action causes diaphragm on inside of pump to pull fuel in on its downward stroke and to push it into carburetor on its upward stroke, internal check valves prevent fuel from going backward through pump. 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 Replacement Mechanical fuel pump is an integral part of valve cover assembly and not serviced separately. 1. Disconnect fuel lines from inlet and outlet fi ttings. Note orientation. 2. Follow procedure for replacing valve cover. Refer to Disassembly and Reassembly. 3. Reconnect fuel lines to inlet and outlet fi ttings and secure with clamps.
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 tests. 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. 3. Check operation of fuel pump. a. Remove fuel line from inlet fi tting of carburetor. b. Crank engine several times and observe fl ow.
Condition Conclusion 20 KohlerEngines.com 66 690 01 Rev. C Fuel at tip of spark plug. Fuel is reaching combustion chamber. No fuel at tip of spark plug. Check fuel fl ow from fuel tank (step 2). 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.