Electric Choke Adjustment

• 1). Determine whether the Holley carburetor choke is opening too fast or too slow. If too fast, the engine will stall or backfire. If opening too slow, the engine will produce black smoke in the exhaust or idle roughly.
  
  
• 2). Remove the air cleaner from the top of the carburetor and start the engine. Loosen the three screws on the carburetor choke cap with a screwdriver.
  
  
• 3). Turn the cap one notch at a time, counterclockwise if the choke is opening to fast and clockwise if it is opening too slow, until you notice the engine smoothing out.
  
  
• 4). Tighten the screws on the cap with a screwdriver and verify that the choke cap opens properly when the engine is warm. Turn the engine off.
  
  

Manual Choke Adjustment

• 1). Start the engine and remove the air cleaner from the top of the carburetor. Determine if the carburetor is idling too fast or too slow and turn the engine off.
  
  
• 2). Locate the fast idle set screw at the base of the black choke cap and turn it counterclockwise with a screwdriver until it is completely open.
  
  
• 3). Unhook the rubber vacuum hose from the vacuum port at the base of the carburetor and connect a vacuum gauge to the port.
  
  
• 4). Start the engine and turn the fast idle set screw with a screwdriver clockwise one quarter turn at a time until the vacuum gauge reads between 1500 and 1600 RPM's and is running smoothly.
  
  
• 5). Shut off the engine and remove the vacuum gauge. Reattach the rubber vacuum hose to the vacuum port and place the air cleaner back onto the top of the carburetor.