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Joined: Sep 2002
Posts: 47
Shade Tree Mechanic
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OP
Shade Tree Mechanic
Joined: Sep 2002
Posts: 47 |
What causes backfiring in a 216 with a W1 carb and a standard dist? I've adjusted points, timing, idle speed and mixture. Engine idles nice but when speeded up it bucks a bit and backfires(popping from the tail pipe). Rotating the distributor minimizes but does not eliminate the popping. Will check plugs next. Could it be valve adjustment? Also, the carb float is not the correct W1 float but seems to function OK, no lack of fuel or flooding(overflowing). Thanks, Larry
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Joined: Nov 2001
Posts: 29,863
Tech Advisor ChatMaster - 25,000
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Tech Advisor ChatMaster - 25,000
Joined: Nov 2001
Posts: 29,863 |
The Mangy Old Mutt
"If It's Not Junk.....It's Not Treasure!"
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Joined: Jan 2002
Posts: 30,701 Likes: 141
ChatMaster - 25,000
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ChatMaster - 25,000
Joined: Jan 2002
Posts: 30,701 Likes: 141 |
All W-1 's from 1932-49 used the same float...doubt if its the wrong float.Would check its adjustments as JYD suggested.
Other problems---tight valves-or burnt or sticking valve.A bad (leaky) intake valve will cause it to pop back thru the carb...exhaust thru the tail pipe.Check the compression.A miss-fire in the ignition system could cause the problem...such as cap or wires...pull the cap and wires off one of your other cars and try...
Gene Schneider
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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 |
Replace the condenser in the distributor. 
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: Feb 2002
Posts: 1,178
ChatMaster - 1,000
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ChatMaster - 1,000
Joined: Feb 2002
Posts: 1,178 |
I would first check the spark plug wires for proper location making sure none are crossed, also seperate them so that there is no opportunity for cross fire. Check the distributor cap for cracks, or moisture. As suggested a compression check for a leaky or sticky valve may be in order.
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Joined: Jan 2002
Posts: 30,701 Likes: 141
ChatMaster - 25,000
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ChatMaster - 25,000
Joined: Jan 2002
Posts: 30,701 Likes: 141 |
Or broken valve spring.....I would begin with the condenser
Please inform us later as to what the problem was.
Gene Schneider
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Joined: Dec 2001
Posts: 203
Backyard Mechanic
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Backyard Mechanic
Joined: Dec 2001
Posts: 203 |
Hi Larry,
It sounds like the accelerator pump is bad or needs to be adjusted. What is happening is during acceleration the engine needs more fuel - the job of the accelerator pump. I suspect if the float level and float drop is ok, then check your accelerator pump - nicks tears or just wear.
Does the bucking stop if you pull the choke on just a little? If yes, does the bucking stop once the engine is fully warm?
Also, check to see if your vacuum advance is working and you have no vacuum leaks.
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Joined: Jan 2002
Posts: 30,701 Likes: 141
ChatMaster - 25,000
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ChatMaster - 25,000
Joined: Jan 2002
Posts: 30,701 Likes: 141 |
Larry will have a busy weekend with all the tips he has recieved. 
Gene Schneider
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Joined: Mar 2005
Posts: 22
Grease Monkey
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Grease Monkey
Joined: Mar 2005
Posts: 22 |
I would also check the spark coil, they can do some wierd things. I have had them act like that especially when they are warmed up. Good luck and check all of the other sugestions too. :p
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