How to Clean and Rebuild a Carburetor

Early model vehicle engines relied on a carburetor to inject the right amount of fuel into the cylinders to burn during operation. Inside the carburetor is a system of floats and jets that operate under pressure from the fuel system and vacuum lines that regulate the flow of fuel. Gasoline can leave behind residue upon drying in place, and unspent fuel can make an old carburetor run poorly. A good clean carburetor will ensure the smooth running of the engine, and a rebuilt carburetor is one that has all the old residue removed and new parts installed. Clean and rebuild a carburetor in under four hours.

Difficulty: Moderate

Instructions

Things You'll Need:

• Carburetor Carburetor Gasket Cleaning Fluid (Dip/Spray) Compressed Air Retractable Magnet Wrench Screwdriver Needle Nose Pliers Rags

1. Place the carburetor on a clean, well-lit workbench with the top facing up. remove the top cover of the carburetor by loosening the fasteners that secure it to the carburetor body. Most fasteners will be screws that can be removed using the appropriate screwdriver. For small nuts and bolts, have a crescent wrench available to remove the fasteners that are not screw type. Take the top of the carburetor off to expose the float and pump of the accelerator. Dispose of the old gasket that was in between the top and bottom carburetor plates.

2. Take the top of the carburetor to a catch container and completely spray with carburetor cleaner. Use a stiff paint brush that is free of debris to clean inside the edges and corners of the cover. Set to the side for drying. Any linkage that is attached to the top cover of the carburetor can be wiped down with an oiled rag to lubricate the joints and connectors after cleaning. Spray the entire top of the carburetor with compressed air so that no fluids are left behind before connecting the parts back together.

3. Use a magnet to fish out the check valves from the base of the carburetor. Use a screwdriver to move the jets in and out and check the jets for damage. Any scratches or dings in the jets can cause an irregular fuel flow resulting in poor performance. Install new replacement jets for the best rebuild results. Seat the jets in their threaded ports and secure to spec. Take the entire base of the carburetor to the catch container and spray with the cleaning solution or dip the unit into carb cleaning solution. Use a brush to clean inside and around tight corners and flow paths that have residue built up.

4. Blow out the entire carburetor base with compressed air prior to assembling the carburetor back together. Lightly oil the accelerator pump prior to inserting the top carburetor cover to the carburetor base. Install a new carburetor gasket that has also been lightly oiled in between the top and bottom portions of the carburetor. Fasten the pieces back together using the screws and bolts of the top carb cover and tighten. Make sure all the linkage is reconnected and that all the parts are working before installation.

5. Install the carburetor on the engine and connect the fuel lines and accelerator cables to the linkage. Press the accelerator pedal to see if the system is injecting fuel into the plenum when activated. Pump fuel into the system and then attempt to start the engine. Once started, check that the jets are set appropriately for even idling and acceleration. After testing the newly rebuilt carburetor will run smoothly without the extra gasoline residue and buildup that can result from years of use.

Tips & Warnings

• Use a tray to catch all the parts of the carburetor during the rebuild. If a check valve comes out, you do not want it rolling off the bench and getting lost.
• Carburetor cleaning solutions are highly combustible. Never work with these solutions while smoking or around open flame.

Resources

• Experts in Carburetors

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