carb troubles - The 1947 - Present Chevrolet & GMC Truck Message Board Network

texnician01 · 01-27-2003, 02:10 PM

I've got a 69 with a 292 that I just drove out of the shop the other day after a 3 year restoration. It has a single barrel holley model number 1940 on it. the carb works good but it is acting up at the moment. it has a dead spot off of idle witch is exactly where it runs when cruising so I get this bucking and surging thing going on. then if I start up a hill on the highway or interstate it does the same thing wants to cut out and buck. the more I push the pedal the worse it gets. I jetted the thing down just a little before I stopped driving it but don't remember it doing this. If I reach down and pull out the choke a little it almost goes away, but I can't run around with the choke pulled out all the time. I'm sure it's not ignition cause I have an ignitor and most of the rest of it is in good shape. any suggestions?

thanks

Nathan

70c10 · 01-27-2003, 02:21 PM

Have you checked the fuel filter?

texnician01 · 01-27-2003, 02:27 PM

has a brand new filter on it.

70c10 · 01-27-2003, 02:32 PM

Does it have the original accelerator pump?

texnician01 · 01-27-2003, 02:35 PM

had a rebuild kit put in it about 6 months before I stopped driving it.

nathan

SWINGSAX68 · 01-27-2003, 02:40 PM

Hmm....same problem I had......very similar...not as much bucking...but it wouldn't clear an incline for damn sure...check the vacuum advance and makesure to check the timeing as well. that may help...just from what I think is going on.

68chevy10 · 01-27-2003, 03:07 PM

i had a similar problem with my 350, it was the mechanical fuel pump, it was puting out to much presure, does it blow black smoke?

texnician01 · 01-27-2003, 03:09 PM

ya it does and it has a fairly new pump on it.

68chevy10 · 01-27-2003, 03:14 PM

ya my pump was also brand new, check fuel presure, it should be about 7-9 psi if i'm not mistaken. mine was putting out 14-15 psi, i don't know why, i installed a regulator on it and the problem was cured

sneakysnake · 01-27-2003, 03:35 PM

sounds like a restricted main jet, by being able to pull the choke and it smooth out,you richen the mixture,sitting up may have produced some crud

01-27-2003, 02:10 PM	#1
texnician01 Senior Member Join Date: Mar 2002 Location: 12 Miles South of Des Moines, Iowa Posts: 359	carb troubles I've got a 69 with a 292 that I just drove out of the shop the other day after a 3 year restoration. It has a single barrel holley model number 1940 on it. the carb works good but it is acting up at the moment. it has a dead spot off of idle witch is exactly where it runs when cruising so I get this bucking and surging thing going on. then if I start up a hill on the highway or interstate it does the same thing wants to cut out and buck. the more I push the pedal the worse it gets. I jetted the thing down just a little before I stopped driving it but don't remember it doing this. If I reach down and pull out the choke a little it almost goes away, but I can't run around with the choke pulled out all the time. I'm sure it's not ignition cause I have an ignitor and most of the rest of it is in good shape. any suggestions? thanks Nathan __________________ 69 C-10, 340HP 327 55 chevy 4 door 150 47 Willys CJ-2A 05 Harley Night Train 06 1200 Sportster (Wife's bike) 70 Honda CL350 OIF2 & OIF7 Veteran Nathan & Tiffany

01-27-2003, 02:21 PM	#2
70c10 67-72 Addict! Join Date: Feb 2002 Location: The TAX State! Posts: 7,856	Have you checked the fuel filter? __________________ Jim 1970 C/10 Fleetside w/Ghost Flames Lowered 4.5" front and 4" rear (Raked) 355/350 Turbo w/shift kit 10" Redneck Performance Verter w/2500 stall Hooker Super Comps part#2808-1 Performer RPM Air-Gap 12 Bolt w/3:73 gears- Eaton Posi Comp Cams XE262 with 1.6 Crane Energizers, Road Demon 625 and Brodix IK 180 heads

01-27-2003, 02:27 PM	#3
texnician01 Senior Member Join Date: Mar 2002 Location: 12 Miles South of Des Moines, Iowa Posts: 359	has a brand new filter on it. __________________ 69 C-10, 340HP 327 55 chevy 4 door 150 47 Willys CJ-2A 05 Harley Night Train 06 1200 Sportster (Wife's bike) 70 Honda CL350 OIF2 & OIF7 Veteran Nathan & Tiffany

01-27-2003, 02:32 PM	#4
70c10 67-72 Addict! Join Date: Feb 2002 Location: The TAX State! Posts: 7,856	Does it have the original accelerator pump? __________________ Jim 1970 C/10 Fleetside w/Ghost Flames Lowered 4.5" front and 4" rear (Raked) 355/350 Turbo w/shift kit 10" Redneck Performance Verter w/2500 stall Hooker Super Comps part#2808-1 Performer RPM Air-Gap 12 Bolt w/3:73 gears- Eaton Posi Comp Cams XE262 with 1.6 Crane Energizers, Road Demon 625 and Brodix IK 180 heads

01-27-2003, 02:35 PM	#5
texnician01 Senior Member Join Date: Mar 2002 Location: 12 Miles South of Des Moines, Iowa Posts: 359	had a rebuild kit put in it about 6 months before I stopped driving it. nathan __________________ 69 C-10, 340HP 327 55 chevy 4 door 150 47 Willys CJ-2A 05 Harley Night Train 06 1200 Sportster (Wife's bike) 70 Honda CL350 OIF2 & OIF7 Veteran Nathan & Tiffany

01-27-2003, 02:40 PM	#6
SWINGSAX68 Now the others dig........ Join Date: May 2002 Location: San Antonio, TX Posts: 1,520	Hmm....same problem I had......very similar...not as much bucking...but it wouldn't clear an incline for damn sure...check the vacuum advance and makesure to check the timeing as well. that may help...just from what I think is going on. __________________ 68 Chevy C10 Stepside Black Primer 78 GMC Longbed White 09 Chevy Silverado Shortbed Granite Blue *LOOKING FOR A 67 4 DOOR IMPALA!!!Just like Sam and Dean Winchester!! 'Cause Mustangs are for p^#$ and you can fit a body in the trunk of a 67 Impala* MEMBER OF THE DRUM BRAKE CLUB Bachelor of Music in Jazz Studies Texas State University-San Marcos, TX Certified Music Educator I hope Mom is up there watching and being my Guardian Angel "I've got a fever.....and the only prescription.....IS MORE COW BELL" -The Legendary: Bruce Dickenson "F#$@ 'em up!!!!!!" -The Legendary: Rogelio Escobar TRUCKY LINKS** http://67-72chevytrucks.com/vboard/s...d.php?t=457750 http://67-72chevytrucks.com/vboard/s...d.php?t=461184 http://67-72chevytrucks.com/vboard/s...d.php?t=472848 http://67-72chevytrucks.com/vboard/s...d.php?t=417541 http://67-72chevytrucks.com/vboard/s...d.php?t=477788

01-27-2003, 03:07 PM	#7
68chevy10 Registered User Join Date: Jan 2003 Location: medicine hat, AB Canada Posts: 11	i had a similar problem with my 350, it was the mechanical fuel pump, it was puting out to much presure, does it blow black smoke?

01-27-2003, 03:09 PM	#8
texnician01 Senior Member Join Date: Mar 2002 Location: 12 Miles South of Des Moines, Iowa Posts: 359	ya it does and it has a fairly new pump on it. __________________ 69 C-10, 340HP 327 55 chevy 4 door 150 47 Willys CJ-2A 05 Harley Night Train 06 1200 Sportster (Wife's bike) 70 Honda CL350 OIF2 & OIF7 Veteran Nathan & Tiffany

01-27-2003, 03:14 PM	#9
68chevy10 Registered User Join Date: Jan 2003 Location: medicine hat, AB Canada Posts: 11	ya my pump was also brand new, check fuel presure, it should be about 7-9 psi if i'm not mistaken. mine was putting out 14-15 psi, i don't know why, i installed a regulator on it and the problem was cured

01-27-2003, 03:35 PM	#10
sneakysnake It's a catastrophic success. Join Date: Jan 2003 Location: Oklahoma Posts: 2,077	sounds like a restricted main jet, by being able to pull the choke and it smooth out,you richen the mixture,sitting up may have produced some crud



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