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How to rebuild a Holley 650 carburetor: (Disassembly and cleaning)

Holley 650 Double Pumper
Holley 650 Double Pumper

The first thing is to place the carburetor in a cleaning tray. Spray the exterior and all holes with carburetor cleaner spray, followed by compressed air. Next remove the four 5/16 inch bolts from the front (primary) and rear (secondary) fuel bowls. If the bowls stick to the metering block, tap them lightly with the handle of a screwdriver while you pull outward. Discard the old gaskets.
Now flip the carburetor over and remove the base plate screws with a Philips screwdriver. Discard the base plate gasket. Inspect the base plate ears for cracks and over- tightening. If cracks are found, you will have to replace the base plate, a part that does not come with a rebuild kit.
Next return the carburetor to an upright position and remove the accelerator nozzle screws with a Philips screwdriver. Pull the nozzles out with pliers. Be careful not to let the small needle under the nozzle fall out. Now unscrew the power valve from the primary metering block (only one power valve on non-dominator carbs) with a 1-inch wrench. If your carb has a choke assembly, pull the small clip off the choke body rod with pliers and then remove the screws from the choke body and pull it off the main carb body. Next inspect the power valve, unscrew the main jets from the metering blocks with a screwdriver, and soak them in carburetor cleaner spray. Save the main jets for the rebuild process. Compare the size stamp of the old power valve with the replacement to ensure it's correct.
Next spray the metering block gasket with gasket remover spray. Remove the old gasket. Inspect the edges of the fuel bowls and the faces of the metering blocks for gasket remains. Scrub any remains away with a soft bristle brush and brief shots of carburetor cleaner spray. Spray the disassembled carburetor, inside and out, with carb cleaner spray.

Next time we will talk about assembly.