A carburetor functions to mix the fuel and air mixture that is used for combustion within the engine. This mixture must maintain a very specific ratio to ensure the proper functioning and output of your engine. Over time, carburetors will need to be rebuilt, as dust and dirt enter their chambers and start to clog them up. You will need extreme patience and meticulous attention to detail to perform a Weber carb rebuild. The rebuild will vary slightly based on your Weber carb model.
Locate the blow up diagram of your specific model of Weber carburetor. Sites such as PelicanParts.com have these diagrams available for free.
Disassemble your carburetor based on your blow up diagram. Do not remove the throttle shafts and bearings, as these are very finely tuned and you will ruin your carburetor if you change these.
Soak all of your metal parts in carburetor cleaner. Be sure that you have labeled all of your parts/containers so that you know where they go when you have to reassemble your carb.
Blast your carb bodies with a mild abrasive such as chalk or talc in a blasting cabinet.
Remove all of your metal parts from the soak and allow them to air dry.
Use a good, thick grease to pack the throttle shaft bearings.
Put grease onto the accelerator pump pushrod and insert it into the carb body.
Place your new carb gasket onto the carb. Be sure that you have placed it into the groove in the correct orientation.
Ensure that the top of your carb is flat otherwise you might have leaks. You can sand it down with a belt sander.
Reinstall your float valve onto the carb top. Use a float-measuring tool to adjust the float level. Once you have adjusted the level, you can tighten the float pivot bolt.
Reinstall your accelerator pump squirters.
Reinstall your carb top by bolting it into place.
Reinstall your idle mixture screws and springs. Bottom them out first and then back them out two turns.
Reinstall the jet stack onto the carb body.
Lubricate your accelerator pump pushrod and the cam and roller mechanism with lube and reinstall them.
