The Ford Barn

1928Pickuppain · 08-04-2010, 09:11 AM

I find my truck has a carb cough when im going down hill or decelerating I know there was thread on it but i can no longer find it. its also back fireing once and a while when going down Hill. It would be greate to look at that old thered but if it cant be found whats you guys ideas?

Brian T · 08-04-2010, 09:40 AM

https://fordbarn.com/forum/showthread...light=backfire

This is maybe what you were looking for

Freddie (Memphis) · 08-04-2010, 10:12 AM

I refrained from posting when I first saw this post this morning, but I suspected a too lean condition. I read the thread listed in the above post and indeed, there are a few lean condition theorists, too.

You didn't mention if you had tried a little richer GAV setting...a little more open, in other words. You might try opening the GAV about another 1/4 turn and see if that addresses your issue. If not, then I'd suspect an air leak somewhere around the carb-to-manifold joint, or around the manifold gasket...both of these will cause a lean condition. If you suspect that...with the engine warmed and idling, try squirting some WD40 around the joints between the carb/manifold and manifold/head. If you get any change in your idle speed...then there's your leak. If no change in idle, then it's something else.

Hope this helps...let us know what you find...

krswen · 08-04-2010, 11:25 AM

somewhere I read recently that the latest WD40 isn't flammable, so won't work for this test .....

Ken

Freddie (Memphis) · 08-04-2010, 12:31 PM

Hell, Ken...I've had a can of WD40 for the last 12 years. I've used it to start balky-starting lawnmowers, a Jaguar 4.2l, and at least two big block V8 Fords after rebuilds. The new stuff may not be flammable, but this can I've got sure as hell is...!

But...that got me to thinking (boy...THAT'S dangerous)...think I'll buy a new can on the way home and test it myself. I would imagine the propellant has changed...maybe that's what was flammable, I dunno.

I'll employ the ol' "TBFO" method of research... Tell By Finding Out

Chris in CT · 08-04-2010, 02:34 PM

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Hi 28pickup, Sounds like your carb is running too lean. Good Luck!

08-04-2010, 09:11 AM	#1
1928Pickuppain Senior Member Join Date: May 2010 Location: Billerica, Ma Posts: 461	Carb Cough and fart I find my truck has a carb cough when im going down hill or decelerating I know there was thread on it but i can no longer find it. its also back fireing once and a while when going down Hill. It would be greate to look at that old thered but if it cant be found whats you guys ideas?

08-04-2010, 09:40 AM	#2
Brian T Senior Member Join Date: May 2010 Location: San Diego,Ca Posts: 1,377	Re: Carb Cough and fart https://fordbarn.com/forum/showthread...light=backfire This is maybe what you were looking for

08-04-2010, 10:12 AM	#3
Freddie (Memphis) Senior Member Join Date: May 2010 Location: Germantown, TN Posts: 109	Re: Carb Cough and fart I refrained from posting when I first saw this post this morning, but I suspected a too lean condition. I read the thread listed in the above post and indeed, there are a few lean condition theorists, too. You didn't mention if you had tried a little richer GAV setting...a little more open, in other words. You might try opening the GAV about another 1/4 turn and see if that addresses your issue. If not, then I'd suspect an air leak somewhere around the carb-to-manifold joint, or around the manifold gasket...both of these will cause a lean condition. If you suspect that...with the engine warmed and idling, try squirting some WD40 around the joints between the carb/manifold and manifold/head. If you get any change in your idle speed...then there's your leak. If no change in idle, then it's something else. Hope this helps...let us know what you find... __________________ Freddie (Memphis) "...an opinon on everything...an expert on nuthin'..." I'm still doin' the rhumba, Baby...I just can't seem to quit. If momma catches us doin' the rhumba....momma would just pitch a fit. I can't help myself....it's much bigger than me. If I were you I'd hang on to a rhumba man like me...!

08-04-2010, 11:25 AM	#4
krswen Junior Member Join Date: Jul 2010 Location: Eureka, CA Posts: 24	Re: Carb Cough and fart somewhere I read recently that the latest WD40 isn't flammable, so won't work for this test ..... Ken

08-04-2010, 12:31 PM	#5
Freddie (Memphis) Senior Member Join Date: May 2010 Location: Germantown, TN Posts: 109	Re: Carb Cough and fart Hell, Ken...I've had a can of WD40 for the last 12 years. I've used it to start balky-starting lawnmowers, a Jaguar 4.2l, and at least two big block V8 Fords after rebuilds. The new stuff may not be flammable, but this can I've got sure as hell is...! But...that got me to thinking (boy...THAT'S dangerous)...think I'll buy a new can on the way home and test it myself. I would imagine the propellant has changed...maybe that's what was flammable, I dunno. I'll employ the ol' "TBFO" method of research... Tell By Finding Out __________________ Freddie (Memphis) "...an opinon on everything...an expert on nuthin'..." I'm still doin' the rhumba, Baby...I just can't seem to quit. If momma catches us doin' the rhumba....momma would just pitch a fit. I can't help myself....it's much bigger than me. If I were you I'd hang on to a rhumba man like me...!

08-04-2010, 02:34 PM	#6
Chris in CT Senior Member Join Date: May 2010 Location: Connecticut Posts: 272	Re: Carb Cough and fart Sponsored Links (Register now to hide all advertisements) Hi 28pickup, Sounds like your carb is running too lean. Good Luck!