Kohler MAGNUM M18

SECTION 6A
FUEL SYSTEMS AND GOVERNORS
Test
Conclusion
1. Check for the following:
A. Make sure the fuel tank contains fuel.
B. Make sure the vent in fuel tank cap is open.
C. Make sure the fuel shut-off valve is open.
2. Check for fuel in the combustion chamber.
A. Disconnect the spark plug leads.
B. Close the choke on carburetor.
С. Crank the engine several times.
D. Remove the spark plugs and check for fuel at
tips.
2. If there Is fuel at tips of spark plugs, fuel is reach-
ing the combustion chambers.
If there is no fuel at tips fo spark plugs, check for
fuel flow from the fuel tank. (Test 3).
3. Check for fuel flow from the fuel tank to fuel
pump.
A. Remove the fuel line from inlet fitting of fuel
pump.
B. Hold the line below the bottom of tank. Open
the shut-off valve (if so equipped) and observe
flow.
4. Check operation of fuel pump.
A. Remove the fuel line from inlet fitting of
carburetor.
B. Crank the engine several times and observe
flow.
FUEL FILTER
Some engines are equipped with an in-line fuel filter.
Visually inspect the filter periodically. Replace when
dirty with a genuine Kohler filter. Refer to Figure 6A-2.
Fuel
Filter
Figure 6A-2. In-Line Fuel Fitter.
3. If fuel does flow from line, check for faulty fuel
pump. (Test 4).
If fuel does not flow from line, check for clogged
fuel tank vent, shut-off valve, screen, and fuel
lines.
. If fuel does not flow from line, check for clogged
fuel line. If line is unobstructed, fuel pump is faulty
and must be replaced.
If fuel does flow from fuel line, the carburetor is
probably faulty. Refer to the “Carburetor” portion of
this section.
FUEL PUMP
Most Magnum engines are equipped with a mechani-
cally operated fuel pump. On applications using a
gravity feed fuel system, the fuel pump is not used
and the pump mounting pad on the crankcase is
covered.
The fuel pump body is constructed of a nylon material.
The nylon body insulates the fuel from the hot engine
crankcase and prevents fuel from vaporizing inside the
pump.
Operation
The mechanical fuel pump is operated by a lever
which rides on the engine camshaft. The lever trans-
mits a pumping action to the diaphragm inside the
pump body. Tnis pumping action draws fuel in
through the inlet check valve on the downward stroke
of diaphragm. On the upward stroke of the dia-
phragm, the fuel is forced out through the outlet check
valve. Refer to Figure 6A-3.
6A.2