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Joined: Dec 2001
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ChatMaster - 2,000
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OP
ChatMaster - 2,000
Joined: Dec 2001
Posts: 2,142 Likes: 3 |
I have taken out my 31 for the second time this year, I noticed today while using engine compresion to slow down a steep grade in second gear that there were a few backfires out the tail pipe. It runs good otherwise, no problems. I do not have the original carb, there is a marvel carb on the car. I had the carb off of the car because the float was stuck. This did not happen until I touched the carb. There is brass rod that is what I believe to be a power valve adjustment could that be out of whack? need some direction
John
John
1954 Belair Sport Coupe
1960 2 door Impala Hardtop 348/340HP 4spd
1962 2 door Impala Hardtop 409/409 4spd
1962 2 Door Biscayne Sedan 327/250 Auto
1977 Monza Mirage 305 4 Speed
1988 Celebrity Wagon
2018 GMC Sierra 2500 HD Diesel
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Joined: Dec 2001
Posts: 10,379 Likes: 1
Technical Advisor ChatMaster - 10,000
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Technical Advisor ChatMaster - 10,000
Joined: Dec 2001
Posts: 10,379 Likes: 1 |
Backfiring is generally caused by the throttle not being completely closed. It can also be caused by a badly worn throttle shaft.  
RAY Chevradioman http://www.vccacolumbiariverregion.org/1925 Superior K Roadster 1928 Convertible, Sport, Cabriolet 1933 Eagle, Coupe 1941 Master Deluxe 5-Passenger Coupe 1950 Styleline Deluxe 4-Door Sedan 1950 Styleline Deluxe Convertible 2002 Pontiac, Montana, Passenger Van 2014 Impala, 4-Door Sedan, White Diamond, LTZ 2017 Silverado, Double Cab, Z71, 4X4, White, Standard Bed, LTZ If you need a shoulder to cry on, pull off to the side of the road. Death is the number 1 killer in the world.
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Joined: Nov 2001
Posts: 19,758 Likes: 64
ChatMaster - 15,000
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ChatMaster - 15,000
Joined: Nov 2001
Posts: 19,758 Likes: 64 |
John,
Is the problem backfiring through the carburetor or through the tail pipe? The noise is similar but cause is different. If through the tail pipe it is as Ray wrote, most likely feeding more fuel than can be burned in the cylinders building up in the exhaust and igniting. As long as it does not blow the exhaust system apart (very unlikely) it is not a big problem. Just uses a bit more of that expensive liquid.
If actually firing back through the carburetor it is most often leakage of air past the throttle shaft or other problem causing a lean burn condition. Ray got that one too. It can cause damage to pistons, valves and headgaskets if it persists. Also not likely to be a problem. You can check the color of the spark plug electrode insulator and get a good idea of which is happening. Examining the color of the inside of the tailpipe will also give an indication of lean or rich combustion.
How Sweet the roar of a Chevy four!
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Joined: Dec 2001
Posts: 2,142 Likes: 3
ChatMaster - 2,000
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OP
ChatMaster - 2,000
Joined: Dec 2001
Posts: 2,142 Likes: 3 |
Chip,
it is out the back, I am going to play with it a little now.. more to come
John
John
1954 Belair Sport Coupe
1960 2 door Impala Hardtop 348/340HP 4spd
1962 2 door Impala Hardtop 409/409 4spd
1962 2 Door Biscayne Sedan 327/250 Auto
1977 Monza Mirage 305 4 Speed
1988 Celebrity Wagon
2018 GMC Sierra 2500 HD Diesel
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Joined: Jul 2002
Posts: 205
Backyard Mechanic
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Backyard Mechanic
Joined: Jul 2002
Posts: 205 |
could also be a vacuum leak
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