Prior to performing major carburetor service work, a thorough road test and check of carburetor adjustments should be done first. Carburetor problems usually manifest as flooding, hard-starting, stalling, severe backfiring and poor acceleration. A carburetor that's leaking fuel or covered in wet deposits also require attention. Performance problems may also be related to loose, out-of-adjustment or malfunctioning engine or electrical components. The best way to analyze issues with a carburetor is to follow a step-by-step approach to eliminating each potential issue before deciding to rebuild the carburetor.
Inspect all vacuum hoses and actuators for leaks and correct installation.
Tighten the intake manifold and carburetor mounting nuts/bolts with a socket wrench.
Perform a cylinder compression test.
Inspect the spark plugs. Clean or replace any that are not operating properly.
Inspect the ignition primary wires for damage. Check the ignition timing.
Check the fuel pump for proper operation and verify the fuel pressure meets the specifications.
Check the heat control valve in the air cleaner for proper operation.
Check the air filter element; replace if necessary. Check the crankcase ventilation system.
Check the fuel filter and replace if necessary. Ensure the fuel filter is not restricted prior to doing a full replacement. Check the choke, which should be completely open at normal engine operating temperatures. Check for fuel leaks and kinked or dented fuel lines.
Ensure the exhaust system is not congested.
Ensure the EGR valve is operating properly. Check the accelerator pump operation with the engine off by removing the air cleaner cover and operating the throttle as you look into the carburetor throat. You should see a stream of gasoline enter the carburetor.
If all other potential problems have been eliminated, the carburetor should be overhauled or replaced. It is best to purchase a carburetor overhaul kit, which provides step-by-step instructions specific to your vehicle.
