You can certainly save yourself some frustration by cleaning the gum and varnish off your old carburetor, allowing it to function properly. Carburetors are subject to all manner of gunk- dirt, oil, fuel, grease, just about anything that is involved in your engine often finds its way to your carburetor. Over time this gunk clogs the internals, varnishes the guts, and leads to poor performance. Even cleaning up the exterior of your carb can help bring back the performance of your vehicle. Here’s how to clean a carburetor the right way.
There are several types of carb cleaners: in-tank cleaners that go into the fuel to clean up the interior passages, spray cans to clean the outside (and inside when rebuilding), and the all inclusive dunk tank that takes the entire carb in a basket in a pail of cleaner.
Fuel tank additives, such as CRC 05061 fuel injector and carb cleaner treat the inside of your carburetor to help remove varnish and gunk from the inside. These products work fairly well to clean a carburetor in running vehicles that just need a little bit of clean up. If the car has been sitting a while or is not running well at all, then an in-tank additive is not going to get you very far. It won’t hurt, but chances are you need something more serious like a rebuild.
You may not realize it, but even though the magic happens inside the carb all that gummed up gunk on the outside of the carb makes a difference too. If the linkages for the throttle, choke, and transmission are gummed up they won’t operate correctly and you will be fighting all kinds of battles. When it comes to tuning your carb you want all the adjusters to be clean as well.
Clean the outside of the carb using the spray can by soaking it down, concentrating on the grime.
Scrub it with a soft bristled brush to get the grime broken up.
Blast it again to clear the residue, and wipe it off.
Inside the air horn (under the air cleaner) carb cleaner is the best way to clean up the squirters that meter out the fuel to the engine. With the engine off crank the throttle all the way open while watching the squirters. You should see two shots of fuel as you rotate the throttle, and then two more shots in the rear bowls (if a 4-barrel) as you hit the halfway point and go to wide open throttle. Only do this with the engine off! If one or more barrel is not squirting, you have a problem.
Use the straw on the can to spray the squirter. Try to get right up on it. Work the throttle again. Try this a couple times, if that does not free it up, then you likely need a rebuild.
Once you determine that you need a rebuild, pick up a gallon of carb dip. This usually comes in a gallon pail with a small basket. Your carb must be fully disassembled to get the parts in the basket. Follow the instructions. The dip is very similar to the stuff in the spray can, but more concentrated. This stuff can actually last for years, so don’t throw it away. It is great for cleaning up old parts. Just let it soak, rinse and reassemble.
Another excellent use for the spray can carb clean is checking for vacuum leaks. With the engine running at idle, use the can with the straw installed and spray suspected vacuum leak areas. If the engine bogs down and then recovers, that is your leak.
Check out all the chemical products available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on how to clean a carburetor, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.
A life-long gearhead, Jefferson Bryant spends more time in the shop than anywhere else. His career began in the car audio industry as a shop manager, eventually working his way into a position at Rockford Fosgate as a product designer. In 2003, he began writing tech articles for magazines, and has been working as an automotive journalist ever since. His work has been featured in Car Craft, Hot Rod, Rod & Custom, Truckin’, Mopar Muscle, and many more. Jefferson has also written 4 books and produced countless videos. Jefferson operates Red Dirt Rodz, his personal garage studio, where all of his magazine articles and tech videos are produced.