carb "puffs" when under load

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Oct 4, 2001 | 08:16 PM

kameleon

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From: USA

carb "puffs" when under load

After I did all the mods to my truck (the new intake, cam, carb, and headers) I noticed that my carb "puffs" or kinda backfires (not through the exhaust pipe but through the carb itself). It mainly does it when I either don't downshift in time or when I floor the gas and shift quickly. What could be the deal?

D. Brooks
kameleon25(No Email Addresses In Posts!)
1980 F-150 "Flare side" Custom
4.9L I6
Offenhauser DP 4bbl intake
Edelbrock 600cfm Elec choke carb
Dynomax standard series headers
Crane Cams PerformerMax 270H cam
Borg Warner T-18 (that will pull the titanic)
9" rearend (not sure of ratio)
I Love My Truck!

Oct 5, 2001 | 01:15 AM

hood

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Joined: Sep 2000

Posts: 385

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From: Flat Rock, Michigan

carb "puffs" when under load

kameleon:
Just a hunch here...Usually when a carb backfires up through the throat it indicates an air/fuel mixture that is too LEAN. Try richening up the air/fuel mixture.

1981 F-150 2WD STYLESIDE P/U
4.9L 1 BBL CARB
C6 AUTO
2.73:1 LIMITED SLIP REAR AXLE
STABILIZER BARS FRONT & REAR
6100 LB GVWR PACKAGE
ORIGINAL OWNER
203,600 PLUS MILES
100% STOCK & UNREBUILT
BUILT FORD TOUGH!!!

Oct 5, 2001 | 05:58 AM

kameleon

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From: USA

carb "puffs" when under load

Thanks. I will try "richening" the mix. I did have to run the carb all the way lean before to keep it from ideling itself to death (in another post) but after adding the 1" carb spacer I can run it richer. I guess I still have some fine tuning to do.

D. Brooks
kameleon25(No Email Addresses In Posts!)
1980 F-150 "Flare side" Custom
4.9L I6
Offenhauser DP 4bbl intake
Edelbrock 600cfm Elec choke carb
Dynomax standard series headers
Crane Cams PerformerMax 270H cam
Borg Warner T-18 (that will pull the titanic)
9" rearend (not sure of ratio)
I Love My Truck!

Oct 5, 2001 | 06:47 AM

chip58

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Joined: Apr 2001

Posts: 92

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carb "puffs" when under load

Different lean. If you need to richen the cruise mixture, you'll need to change the metering rods in your Edelbrock.

Oct 5, 2001 | 04:28 PM

kameleon

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Senior User

Joined: Sep 2001

Posts: 172

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From: USA

carb "puffs" when under load

Ok, I adjusted the mix with the 2 adjustment screws on the front. Is this not how it is done?

D. Brooks
kameleon25(No Email Addresses In Posts!)
1980 F-150 "Flare side" Custom
4.9L I6
Offenhauser DP 4bbl intake
Edelbrock 600cfm Elec choke carb
Dynomax standard series headers
Crane Cams PerformerMax 270H cam
Borg Warner T-18 (that will pull the titanic)
9" rearend (not sure of ratio)
I Love My Truck!

Oct 5, 2001 | 07:16 PM

chip58

Junior User

Joined: Apr 2001

Posts: 92

Likes: 0

carb "puffs" when under load

No, it's not. The two screws in front adjust the idle mixture. Metering rods drop into the top of the carburetor, and control the cruise mixture in Edelbrocks.
I suggest that you buy a book on Edelbrocks, or talk to a knowledgeable speedshop before you go much further.