Inside the Chevrolet Corvair Carburetor
Sooner or later, the Corvair owner will need to clean or maintain the 2 or 4 carbs on their engine. Even these carbs are basic when compared to carbs 15-20 years later, they still require tuning or cleaning.
To ignore this chore is to want idle problems or acceleration issues that may suddenly, and without warning, stall you at a major intersection or worse, cause an accident because the acceleration put you in Harm's Way suddenly. Even the newbie can do this--it may take them longer, but the chore will be done and you know the carbs are clean. Granted, idle problems can be caused by a myriad of potentials:
- dirty fuel lines or gas tank
- dirty jets inside the carburetor
- air leaks around the throttle shaft
- vacuum leaks around the carb
- ignition issues
The above are some of the causes. If your Corvair has been sitting around for years, chances are the gas has changed in the tank or carb, solids form. Even though the stone fuel filters on the Corvair carbs can prevent some of this from entering the carb, micro size pieces can filter through and clog your small jet holes. When this happens, idle is rough or worse. Each carb takes about 30-45 min.
Cleaning the carbs once a year is good idea especially if your Corvair's gas tank is still the original one. 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. Once completed, carefully remove the top of the carburetor. There will be gas inside the carb. Usually it is half full. Be careful and don 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 is between the gas bowls. This part is what you clean. On the right, is the top of the Carb you just removed 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. In the photo above, directly to the left in the bronze colored gas is a 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, use a paper clip to insert it into all holes to clear clogs. Use Carb spray cleaner and spray into all the holes. The cluster has two columns. The more narrow one is what usually is clogged at the end and cause bad idling or no idle. Spray air into all the holes to clear. 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 clusted 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, the vacuum advance, reconnect the tubes, chokes and linkages you removed.