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Classic/Antique Car Repair/1964 Chevy belair 230

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Question
My car recently started back firing through the carburetor while under a load.ive tried adjusting the distributer with no luck. I'm about at my wits end any help would greatly be appreciated.

Answer
I would assume that this happens on acceleration or when the engine is under load. There are three areas that I would first check. First I would check the distributor cap to make sure there are no cracks that run from one spark plug terminal to another. The second would to be sure that the accelerator pump in the carburetor is working. To do this with the engine off remove the air cleaner. Using a flash light look down into the throat of the carburetor and quickly open the throttle. You should see a stream of gas if the engine is a six cylinder and two stream of gas with an eight squirt out. If the accelerator pump is not working when you step on the gas the engine will go lean and backfire and bog. If the accelerator pump is working and the cap is not cracked I would check the compression on the engine. A burned intake valve will cause the engine to backfire up through the carburetor. A burned valve will give more than one pop back up through the carb, as it will pop each tie that cylinder fires.

Classic/Antique Car Repair

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Brad Sears

Expertise

All automotive including antique and collectible. However if the car has been modified I can only answer in general terms and maybe get you pointed in the right direction.

Experience

Automotive tech instructor. Syndicated auto columnist 1970's though the early 1990's. Syndicated auto radio talk show, Ask Brad About cars, CBS Radio 70's through 90's TV Show "Last Chance Garage" 1980's PBS-TV syndicated. Auto instructor for the following companies: Fram Autolyte Holly Carter AMF Ford Motor University Of Conn Blue Hills Technical School Sugar River Technical Center Grew up in a family garage in Needham Mass and turned wrenches from the age of 14.

Publications
Manchester Union Leader, Nashua Telegraph, Motor Service Magazine, Yankee Magazine, Popular Mechanics (Saturday Mechanic early 80's), Los Angeles Times, New York Times, and lots more.

Education/Credentials
More than I care to remember. Basically Franklin Technical Institute in Boston, Northeastern University, Fitchburg State Teachers College, Tufts University, and a lot of factory schools along the way.

Awards and Honors
Moto Award winner. And much more.

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