How to Troubleshoot a Walbro Carburetor

The Walbro carburetor was one of the most reliable carburetors ever made. You will find this type of carburetor on older vehicles prior to the invention of electronic fuel injection. Vacuum pressure draws air into the carburetor and mixes with gasoline, which is then drawn into the engine for combustion. When you suspect that your carburetor is not functioning properly, troubleshoot it to determine what's wrong.

Things You'll Need

• Screwdriver

Instructions

1. Start the engine. Listen to the idle, and check the idle speed displayed on the tachometer. It should be between 500 and 800 rpm.

2. Open the hood and check the adjustment screws. At the base of the carburetor are two adjustment screws you can turn to adjust the air flow rate. Turn the screws counterclockwise. If the idle speed doesn't improve, then you may have a dirty filter screen (the most common problem with the Walbro carburetor).

3. Remove the screw on the side of the carburetor, and check the screen underneath the screw plate. If it is dirty, you should clean or replace it.

Tips & Warnings

• For specific information about your vehicle's Walbro carburetor, consult the particular vehicle's manual (see Resource).

Resources

• Automobile Service Manuals