DIAGNOSIS
POSSIBLE CAUSE
CORRECTION
COMPLAINT: Poor Fuel Economy (font)
Satisfactory high load performance but high fuel consumption at normal cruising conditions.
Economizer stem held down or power valve stuck open.
Check economizer stem for freedom of movement. Check for damage to economizer diaphragm and other evidence of air leaks past diaphragm. Remove power valve and inspectfor cleaninless, damage, proper operation, and size stamped on valve body. Check power valve gasket for splits or other evidence of leakage. Use new gasket when installing power valve. In extreme cases, remove carburetor and check entire vacuum passage in throttle body, main body, and cover for clogging. Replace faulty parts only with authorized Holley replacement parts.
Race engine at constant high speed and observe both pump nozzles. Even the slightest continual discharge affects economy.
Fuel bleeding from accelerating pump nozzles.
Check pump discharge needle and its seat for damage or foreign matter which would prevent needle from seating properly. Replace damaged or worn needle with authorized Holley replacement part. Stake needle as described in "Reassembly" section of this manual.
Choke plates not fully opened when engine is warmed up.
Faulty automatic choke operation.
Check choke linkage for binding or damage. Check thermostat setting. (Must be within two marks of center index). Check condition of fresh air tube f rom carburetor. With engine idling, check for air leaks between choke housing and manifold. Be sure choke housing is mounted tightly to manifold. Use new gasket when installing choke.
COMPLAINT: No Governor Action
Engine speed excess of manufacturer specifications.
Damaged or leaky diaphragm, faulty connections, damaged or leaky vacuum lines.
Check all governor lines and connections. Remove governor diaphragm and check for holes and elongated screw holes from over stretching.
Engine speed excess of manufacturer specifications.
Plugged or wrong size by-pass jets spinrf r valve speed set too high.
Check by-pass jets for cleanliness and correct size. Check spinner valve.
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