How to Rebuild an International Scout Holley Two-Barrel Carburetor

Hard starting, rough idling, poor fuel mileage and hesitation under acceleration can all be attributed to a dirty or damaged carburetor. Rebuilding a two-barrel Holley carburetor is a fairly simple process, but not all carburetors can be rebuilt. If the throttle shafts are leaking air or if the castings are damaged, the carburetor must be replaced. Most International Scout Holly two-barrel carburetors have a small ID tag containing the model number. Having the exact model number is preferable, but it is possible to order a rebuild kit by knowing the year, make, model and the engine size of the vehicle.

Instructions

Rebuilding an International Scout Holley Two-Barrel Carburetor

1

Lay a sheet or drop cloth across the work area to catch any small parts that could be easily lost or overlooked. Clean the outside of your International Scout Holly two-barrel carburetor with a small, nylon-bristled brush to remove heavy debris. Spray all holes with a carburetor cleaner that is safe for both plastic and soft-metal parts.

2

Remove all attached hoses from the carburetor. Inspect each for wear and damage. Replace cracked or thin hoses before you install the rebuilt carburetor onto the vehicle.

3

Remove the bolts from the corners of both fuel bowls. Gently tap each bowl with a rubber mallet to break the seal, if necessary. Remove the fuel bowls from the metering block.

4

Remove the screws from the baseplate. Use a small scraper and gasket remover to peel off the old gaskets, if necessary.

5

Remove the screws from the accelerator nozzles. Remove the nozzles from the choke tower, using needle-nose pliers. Spray carburetor cleaner on the screws to allow for easier removal, if necessary.

6

Take the power valve out of the primary metering block and unscrew the main jets from both blocks. Discard the power valves O-rings. Clean any remaining gaskets and spray the entire disassembled carburetor and all removed parts with cleaner. Use a small nylon brush to remove any stubborn debris. Discard all old gaskets and replace them with the new ones included in your rebuild kit.

7

Replace the baseplate gasket and screw the baseplate tightly back into place. Reinstall the accelerator nozzles into the choke tower. The nozzle needles must be placed into the holes first to ensure a proper fit. Do not force or shove parts as this could cause damage.

8

Remove the idle screws from each side of both metering blocks and discard the cork O-rings. New ones will be in the rebuild kit. Spray carburetor cleaner into each hole to remove buildup. Install the main jets into both the primary and secondary blocks, insert new O-ring for the power valve and screw the valve into place. Install new idler screw O-rings and screw in the idle screws.

9

Unscrew the faceplate from the accelerator pump and remove the diaphragm, spring and umbrella seal. Replace the seal with a new one and discard the old. Replace the spring, diaphragm and the faceplate. Put the new metering block gasket in place and replace both bowls. Make the bolts finger-tight as the gasket has a tendency to slip. Adjust the gasket, if needed. Once the gasket is properly seated, tighten the bolts.