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What to look for when your Rochester Quadrajet is flooding.

  • The number one problem to look for is leaks around the needle and/or seat. Many rebuilds are ruined by a dirty fuel tank, or filter. Also make sure all old gasket residue is gone.
  • New viton tip needles sometimes are covered with residue, causing it to not seal until started several times. Wiping with mineral spirits can help.
  • Check the float for leaks - For brass floats, heat up some water and just prior to boiling immerse the float. The float will heat up inside and if there is a hole, air will bubble out.
  • Nitrophyl floats (looks like plastic), are tested by weight. 6.5 - 8 grams, depending on which float it is.
  • Move the float up and down by hand - Do you feel anything catching?
  • Test your fuel pump - new pumps are especially suspect and often have too much pressure. Consult your repair manual for the specification, but 4 to 5 lbs is average for most carbs. If your flooding started after a rebuild, then skip this one.
  • Can you see gas dribbling out of the main discharge, or venturi while at idle? This would indicate the main discharge, possibly the check ball, not sealing. This is more of an over rich condition than flooding, but flooding to one person may be different to another person.
  • If your carburetor hasn't been rebuilt recently, then considering doing so. Most carb problems are attributed to dirt. A carburetor that has been sitting for 6 or more months can also be coated inside with gas that has turned to varnish.
  • There is a pull clip that connects the float needle with the float arm. Be sure the clip is not routed in one of the small holes. It should be around the outside of the arm.

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Quadrajet Flooding

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