Small backfire through carb?
#1016699
06/20/11 06:09 AM
06/20/11 06:09 AM
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Joined: Jan 2003
Posts: 2,309
Tomorrow.
Damned67
OP
top fuel
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OP
top fuel
Joined: Jan 2003
Posts: 2,309
Tomorrow.
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Hi All, When attempting to start the car yesterday, I had a nice little fireball in the carb. Background: Engine is a stroked 440 (505 ci) with a 1050 Dominator carb. Car has been driven twice in the past 12 months (but started every 6-8 weeks). Thus, gas is 6-12 months old. Last time I tried to start it, I had issues (it took some effort). Yesterday, it was a nightmare to start. I'd been trying for a few minutes. It could have been flooded? It's cool here at the moment (mid- to high 50s), and there's no choke on the carb. It always seems to be a little tougher to start in the cool weather. Once started, it ran rough until it started to warm up a bit. Timing or valves haven't been touched in the past 12 months. AF ratio seemed a little on the rich side during idle (while warming it up, didn't think to check once warmed). I know that backfiring through the carb is generally a timing issue, but I'm hoping there's a chance that it's due to bad/old gas, lean or rich condition, or something that means I don't need to go looking for a new timing issue (which can't be a good sign if timing hasn't been touched). Opinions? Cheers! 
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Re: Small backfire through carb?
[Re: Damned67]
#1016700
06/20/11 09:03 AM
06/20/11 09:03 AM
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Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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I'd get some fresh gas in there (& in the carb bowl) & holler back
live every 24 hour block of time like it's your last day on earth
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Re: Small backfire through carb?
[Re: Damned67]
#1016702
06/21/11 07:18 PM
06/21/11 07:18 PM
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Joined: Apr 2010
Posts: 10,570
Sunny South Florida
Golden-Arm
I Live Here
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I Live Here
Joined: Apr 2010
Posts: 10,570
Sunny South Florida
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might have a small vacuum leak, or even a valve hanging up. gas is easiest to start with. dump it, flush and refill with fresh new gas. filter too, and i'd clean the bowls and screens, needle seats too, while i was in there. you have verified the correct firing order, on the wires/cap, right? 
"When Tyranny Becomes Law, Rebellion Becomes Duty"
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Re: Small backfire through carb?
[Re: Damned67]
#1016704
06/21/11 10:52 PM
06/21/11 10:52 PM
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Joined: Feb 2005
Posts: 5,221
Branson, Mo.
joedust451
super gas
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super gas
Joined: Feb 2005
Posts: 5,221
Branson, Mo.
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Quote:
Hi All,
When attempting to start the car yesterday, I had a nice little fireball in the carb.
Background:
Engine is a stroked 440 (505 ci) with a 1050 Dominator carb.
Car has been driven twice in the past 12 months (but started every 6-8 weeks). Thus, gas is 6-12 months old.
Last time I tried to start it, I had issues (it took some effort).
Yesterday, it was a nightmare to start. I'd been trying for a few minutes. It could have been flooded?
It's cool here at the moment (mid- to high 50s), and there's no choke on the carb. It always seems to be a little tougher to start in the cool weather.
Once started, it ran rough until it started to warm up a bit.
Timing or valves haven't been touched in the past 12 months.
AF ratio seemed a little on the rich side during idle (while warming it up, didn't think to check once warmed).
I know that backfiring through the carb is generally a timing issue, but I'm hoping there's a chance that it's due to bad/old gas, lean or rich condition, or something that means I don't need to go looking for a new timing issue (which can't be a good sign if timing hasn't been touched).
Opinions?
Cheers!
Normally in "most" cases if fuel is "not" going bad or plugs are "not" foiled.
Spitting back through carb while cold= Lean condition/possibly timing
Kicking back while cranking= timing too advanced
Backfire through carb with flame= intake valve not sealing, firing order wrong, timing way off.
Hard starting= bad vacuum leak, timing slow, bad fuel, foiled plugs, flooding.
I would drop & drain the tank & lines/carb of all fuel, install fresh fuel & new filter.
Check the plugs for soot, replace if needed.
IMO, sounds like a possible vacuum leak or a lean idle curcuit, timing needs attention.
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