Fuel System Tests - Kohler HD Series Service Manual

Fuel System

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 lead.
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 carburetor.
a. Remove fuel line from inlet fi tting of carburetor.
b. Use an approved fuel container to catch fuel, and hold line below bottom of tank to observe fuel fl ow. If engine
has in-line fuel fi lter and no fuel fl ows, replace fi lter.
c. Remove fuel line from outlet fi tting of fuel tank. Check in-nipple fuel fi lter and clean/replace as required.
3. Check operation of fuel shut-off valve (if equipped).
a. Turn fuel shut-off valve ON and OFF and observe operation.
Engines equipped with pulse fuel pump:
4. 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 and observe fl ow. If no fuel fl ow, proceed to step c.
c. Remove fuel line from outlet fi tting of fuel tank. Check in-nipple fuel fi lter and clean/replace as required.
5. Check operation of fuel pump.
a. Remove fuel line from inlet fi tting of carburetor.
b. Hold line from carburetor above fuel tank level. Crank engine several times and observe fl ow. If no fuel fl ow,
proceed to step c.
c. Remove fuel line from tee fi tting and check in-nipple fuel fi lter. Clean/replace as required.
6. Check for a clogged fuel line. If line is unobstructed, check for crankcase vacuum (refer to Troubleshooting
Crankcase Vacuum Test), check for overfi lled crankcase and/or oil in pulse line. If checks don't reveal cause of
problem, replace pump.
Condition
Fuel at tip of spark plug.
No fuel at tip of spark plug.
Fuel fl ows from fuel line.
No fuel fl ow from fuel line.
Fuel fl ows from valve.
No fuel fl ows from valve.
22
Fuel is reaching combustion chamber.
Check fuel fl ow from fuel tank (step 2).
Check operation of fuel shut-off valve (step 3).
Check fuel tank vent, in-nipple fuel fi lter, and fuel line.
Correct any observed problem and reconnect line.
Check for faulty carburetor, refer to Carburetor.
Check for a restriction in fuel shut-off valve or inlet elbow.
KohlerEngines.com
Conclusion
14 690 10 Rev. --