Since the carburetor regulates and mixes the fuel and air
going to the engine, there are two general types of carbure-
tor trouble: too rich a mixture (too much fuel), and too lean
a mixture (too little fuel). Such trouble can be caused by
dirt, wear, maladjustment or improper fuel level in the float
chamber. A dirty or damaged air cleaner can also alter the
fuel to air ratio.
Idle Speed Inspection
Refer to the Idle Speed Inspection in the Periodic Main-
Idle Speed Adjustment
Refer to the Idle Speed Adjustment in the Periodic Main-
Service Fuel Level Inspection
Gasoline is extremely flammable and can be ex-
plosive under certain conditions. Always stop the
engine and do not smoke. Make sure the area is
well-ventilated and free from any source of flame
or sparks; this includes any appliance with a pilot
Fuel Tank (see Fuel Tank Removal)
Carburetor (see Carburetor Removal)
Hold the carburetor in true vertical position on a stand.
Put the fuel tank on a bench, and connect the fuel tap to
the carburetor with a fuel hose.
Connect the fuel gauge [A] to the carburetor drain [B] us-
ing a suitable hose [C].
Special Tool - Fuel Level Gauge: 57001-1017
Hold the gauge vertically against the side of the carburetor
body so that the "middle" line [D] is several millimeters
higher than the bottom edge [E] of the carburetor body.
Turn the fuel tap to the ON position to feed fuel to the
carburetor, then turn out the drain plug [F] a few turns.
Wait until the fuel level in the gauge settles.
Keeping the gauge vertical, slowly lower the gauge until
the "middle" line is even with the bottom edge of the car-
Do not lower the "middle" line below the bottom edge of
the carburetor body. If the gauge is lowered and then
raised again, the fuel level measure shows somewhat
higher than the actual fuel level. If the gauge is lowered
too far, dump the fuel out of it into a suitable container
and start the procedure over again.
FUEL SYSTEM 3-11