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FUEL
SYSTEM-DIAGNOSIS
14-3
Condition
Possible Cause
Correction
(c) Faulty accelerator pump inlet check ball.
(c) Disassemble
the
carburetor. Check the accele-
rator pump inlet, check ball for poor seat or
release. If part is faulty, replace.
(d) Test the fuel or float level in the carburetor.
Adjust as necessary to obtain the correct float
level.
(e) Disassemble the carburetor. Replace the worn
accelerator pump and throttle linkage and
measure for the correct position.
(f) Free up manifold heat control valve, using rec-
ommended solvent.
(d) Incorrect fuel or float level.
(e) Worn accelerator pump and throttle linkage.
(f) Manifold heat valve sticking.
CARBURETOR FLOODS
(a) Cracked body.
O R
LEAKS
(b) Faulty body gaskets.
(c) High float level.
(d) Worn needle valve and seat.
(e) Excessive fuel pump pressure.
POOR PERFORMANCE
MIXTURE
TOO
RICH
(a) Restricted air cleaner.
(b) Leaking float.
(c) High float level.
(d) Excessive fuel pump pressure.
(e) Worn metering jet.
CARBURETOR
MIX-
TURES LEAN
(a) Air leak bypassing the carburetor.
(b) Carburetor has economy metering system.
(a) Disassemble
the
carburetor.
Replace
the
cracked body. Make sure main to throttle body
screws are tight.
(b) Disassemble the carburetor. Replace the de-
fective gaskets and
t e s t
for leakage. Be sure
the
screws are tightened securely.
Test the fuel level in the carburetor. Make
the
necessary adjustment to obtain correct float
level.
Clean and inspect the needle valve and seat.
If
found to be in a questionable condition, re-
place the complete assembly and test the fuel
pump pressure. Refer to specifications for cor-
rect fuel pump pressure.
Test the fuel pump pressure.
If
the pressure i s
in excess of recommended pressure (refer to
Specifications), replace fuel pump.
Remove and clean the air cleaner.
Disassemble the carburetor. Replace leaking
float. Test the float level and correct as neces-
sary, to the proper level.
Adjust the float level as necessary to secure the
proper level.
Test the fuel pump pressure. Refer to specifi-
cations for recommended pressure.
If
pressure
is
in excess of recommended pressure, replace
the fuel pump assembly.
Disassemble the carburetor. Replace the worn
metering iet, using a new iet of the correct size
and type.
(a) Correct the air leak.
(b) Install standard metering jets and/or step-up
wires.
ENGINE RUNS EXCESSIVELY RICH AFTER
COLD
START
CHOKE
SYSTEM
RICH
(a) Choke thermostat adiustment richer than
(b) Choke thermostat distorted rich b y overheating.
(a) Adjust the choke.
(b) Replace, since this problem can be corrected
specified.
by use of proper choke assembly.
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