Holley carburetors, including the 885 model, are popular for their performance and reliability. However, like all carburetors, they can occasionally experience issues. Here are some common problems associated with Holley carburetors, as well as some troubleshooting steps and potential solutions:
If the engine has been sitting for months then the gas probably turned to varnish coating the inside of the carburetor, lines and gas tank. A thorough cleaning is in order.
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Engine Won't Start or Hard Starting:
- Check for proper fuel level in the float bowl.
- Ensure that the choke is functioning correctly.
- Verify that there's no clogging in the main jets.
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Poor Idle or Engine Stalls at Idle:
- Ensure the idle mixture screws are adjusted correctly. Start by turning them all the way in and then back out 1.5 turns as a base setting. Fine-tune from there. Use a vacuum gauge and set at the best idle fluctuation.
- Inspect for vacuum leaks around the carburetor base, intake manifold, or any vacuum hoses. Spray carb cleaner around the base. An RPM change indicates a leak.
- Check the idle air bleeds for any clogs.
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Hesitation or Stumble When Accelerating:
- Inspect the accelerator pump for proper operation.
- Adjust the pump cam and/or nozzle size if necessary.
- Ensure the power valve is not blown and is rated correctly for your engine's vacuum.
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Rich Running Condition (Black Smoke from Exhaust):
- Check the float level. A high float level can cause excessive fuel to be pulled into the engine.
- Verify the power valve is not ruptured.
- Inspect the primary and secondary jets; make sure they're the right size for your application.
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Lean Running Condition (Engine Overheats, Pinging):
- Check the float level. A low float level can starve the engine of fuel.
- Inspect the fuel filter for clogs.
- Ensure there's no blockage in the air bleeds.
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Fuel Overflowing or Dripping from Boosters:
- Check the float level and adjust if necessary.
- Ensure the needle and seat are clean and sealing properly.
- Check for a damaged float which could be causing it to sink and not shut off fuel.
- Check the fuel pump pressure. Refer to the motors manual for correct pressure, otherwise pick 4 lbs.
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Choke Not Operating Correctly:
- Inspect the choke linkage for binding or misalignment.
- Check the electric choke connector (if equipped) for a good connection.
- Ensure the choke thermostat is adjusted correctly for your climate. Choke valve should be closed when cold and open when warm. You may need to open the throttle slightly when cold to allow the valve to close.
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Vacuum Secondary Not Opening:
- Inspect the vacuum diaphragm for any tears or damage.
- Ensure there's a proper vacuum signal to the diaphragm.
- Check the secondary throttle linkage for binding.
