Cleaning the Chevrolet Corvair Carburetor
Why You Need to Clean Your Corvair's Carbs
Sooner or later, the Corvair owner will need to clean or maintain the carburetors on their engine, whether they have two or four carbs.
These carbs require tuning or cleaning.
To ignore this chore is to invite idle problems or acceleration issues that may suddenly, and without warning, stall you at a major intersection or worse, cause an accident because a sudden acceleration put you in harm's way.
Granted, idle problems can be caused by a myriad of potentials causes, including:
- dirty fuel lines or gas tank
- dirty jets inside the carburetor
- air leaks around the throttle shaft
- vacuum leaks around the carb
- ignition issues
If your Corvair has been sitting around for years, chances are solids have formed in the gas in the tank or the carb. Even though the stone fuel filters on Corvair carbs prevent some of this debris from entering the carb, micro-size pieces can filter through and clog your small jet holes. When this happens, you will have a rough idle, or worse.
Cleaning the carbs once a year is a good idea especially if your Corvair's gas tank is still the original one. Each carb takes about 30-45 minutes. Even the newbie can do this—a novice may take longer, but the chore will be done and you know the carbs are clean.
Step By Step
To clean the jets inside the carb, the top of the carb is removed.
Remove the rim perimeter screws that hold the top on. Remove the large bolt. Disconnect all the linkage that would hold it to the lower half. Disconnect the fuel line. Then carefully remove the top of the carburetor.
There will be gas inside the carb. Usually it is half full. Be careful and do not contaminate the gas inside. If something falls into the gas, remove it.
With the top removed, the above picture is what you will see. To the left is the lower portion of the carb with gas in the bowls. The Venturi cluster, between the gas bowls, is what you clean. On the right is the top of the carb you just removed, resting on its back side, showing the floats and choke plate.
Above, remove the two screws that hold the Venturi cluster on the carb. Be careful when removing as small parts may stick and you might lose them. Make sure the gasket is either on the cluster or on the carb. On the left in the photos above is a bronze-colored meter jet. This should be cleaned by using a large paper clip and inserting it into the hole to clear any clogs.
Above is the cluster that is being cleaned. The holes in this are in various places. To clean, insert a paper clip into all the holes, to clear clogs. Spray carb cleaner into all the holes. The cluster has two columns; the narrower column is the one that is usually clogged at the end, causing bad idling or no idle. Spray air into all the holes to clear them. The end result is that when you hold the narrow column up to the light, you should be able to see light at the other end. If you do not, it is still clogged.
The Top Reinstalled
Once cleaned, reinstall the cluster back into the carb as you found it. Since it can only go in one way, there is no room for error, unless you forgot the small cluster gasket or a small part came out and you did not notice. Insert the two screws and tighten the cluster onto the carb.
Now carefully take the top of the carb and place it back on the bottom of the carb, making sure it seats correctly. Verify that the throttle spring works by holding the top of carb and simulating the throttle by flexing it. If it does not flex, lift the top up and reseat and retest.
Reattach all of the screws removed and the vacuum advance, and reconnect the tubes, chokes and linkages you removed.