carb backfire
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Junior User
Joined: Nov 2001
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carb backfire
i recently removed the stock 2bbl off my 400 for a tune up. i followed all the intructions very carefully. when i had it installed and tried to start the car a big fireball came out the top. im new to the carb scene so i need some help here. what do i need to do. i just want to tune it enough so i can take it to work and have someone there help me further. someone said my timing was off, but the carb ran somewhat decent before i took it off so i dont think that would have been affected.
any tips are appreciated.
TrackStar
any tips are appreciated.
TrackStar
Senior User
Joined: Jan 2002
Posts: 229
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carb backfire
my car was missing, backfiring through the carbie and through the exhaust... fixed a vacuum leak and put a new ignition coil/leads/plugs on, and now it works fine. but i think several problems will cause your carb to spit flames.
New User
Joined: Jan 2008
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carb backfire
You can start by loosening the distributor and adjust the timing a little closer to see if the back-firing stops.
Bad timing is a Prime candidate for this.
Dennis
Please Don't Ask Me Any Tough Questions As:
"I'm Saving My Memory For When I Develop Alzheimer's"
78 F-150 429CJ,Silver
w/Explorer Pkge.
641/2-Mustang 260,Pre-World's Fair Car.
64-Fairlane500 S/C waiting for a 390-4spd.
68-Mustang 289-Sunlit Gold 80,892Mi
78-Buick LeSabre 403 4V
84 Volvo DL Wagon
Bad timing is a Prime candidate for this.
Dennis
Please Don't Ask Me Any Tough Questions As:
"I'm Saving My Memory For When I Develop Alzheimer's"
78 F-150 429CJ,Silver
w/Explorer Pkge.
641/2-Mustang 260,Pre-World's Fair Car.
64-Fairlane500 S/C waiting for a 390-4spd.
68-Mustang 289-Sunlit Gold 80,892Mi
78-Buick LeSabre 403 4V
84 Volvo DL Wagon
Thread Starter
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Junior User
Joined: Nov 2001
Posts: 64
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carb backfire
ok, i adjusted the distributor and the backfiring stopped. now it starts fine but wont idle, it just dies unless you stay on the gas. is that just a matter of tuning the carb?
TrackStar
TrackStar
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Joined: Aug 2000
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carb backfire
Trackstar, you need to increase the idle speed a little. Turn the idle speed screw in a little (it's the one located on the throttle linkage, that bottoms on the carb base). When you retarded the timing, this reduced the idle speed.
New User
Joined: Jan 2008
Posts: 0
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carb backfire
First thing you do is :
With the engine warm.
1)Set your static timing at proper rpm.
2)adjust idle to spec 550 rpm in neutral
3)turn one idle screw at a time
4)first clockwise(in) until engine starts to stumble
5)while turning it back out count the number of turns until the engine starts to stumble again
6)Now, Divide the number of turns out in HALF and turn the screw back in that amount
7) Do the same process for the other idle screw
8) reset the idle to spec (Auto >650 RPM in Drive)
See if that helps.
Dennis https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=1733&.jpg
Please Don't Ask Me Any Tough Questions As:
"I'm Saving My Memory For When I Develop Alzheimer's"
78 F-150 429CJ,Silver
w/Explorer Pkge.
641/2-Mustang 260,Pre-World's Fair Car.
64-Fairlane500 S/C waiting for a 390-4spd.
68-Mustang 289-Sunlit Gold 80,892Mi
78-Buick LeSabre 403 4V
84 Volvo DL Wagon
With the engine warm.
1)Set your static timing at proper rpm.
2)adjust idle to spec 550 rpm in neutral
3)turn one idle screw at a time
4)first clockwise(in) until engine starts to stumble
5)while turning it back out count the number of turns until the engine starts to stumble again
6)Now, Divide the number of turns out in HALF and turn the screw back in that amount
7) Do the same process for the other idle screw
8) reset the idle to spec (Auto >650 RPM in Drive)
See if that helps.
Dennis https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=1733&.jpg
Please Don't Ask Me Any Tough Questions As:
"I'm Saving My Memory For When I Develop Alzheimer's"
78 F-150 429CJ,Silver
w/Explorer Pkge.
641/2-Mustang 260,Pre-World's Fair Car.
64-Fairlane500 S/C waiting for a 390-4spd.
68-Mustang 289-Sunlit Gold 80,892Mi
78-Buick LeSabre 403 4V
84 Volvo DL Wagon
Thread Starter
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Junior User
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Posts: 64
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Junior User
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carb backfire
i tried increasing the idle speed to no avail, still dies unless you keep on it above 2000rpm. i re-adjusted the two screws at the bottom front of the carb to ensure the proper amount of fuel. backed them out 1 1/2 from tightened all the way. still no change. im gettin frustrated...
TrackStar
:-X23
TrackStar
:-X23
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