New Carb will only accelerate - The 1947 - Present Chevrolet & GMC Truck Message Board Network

71Ochre · 01-03-2017, 10:11 PM

New here, just posted in the welcome section.

I have a 71 C10 with a 350 and a Rochester Quadrajet. I have installed a new carb and when I start up the truck it just accelerates and the pressure rises.

Any ideas?

**Wrenchbender Ret** · 01-03-2017, 10:50 PM

If you mean the engine just races & won't return to idle, It could be the linkage needs adjusting or the secondary throttles are not closed.

71Ochre · 01-03-2017, 10:52 PM

I am new to carbs. I looked over all of the linkages but not sure what would need adjusted.

**dmjlambert** · 01-03-2017, 10:57 PM

I think there should be a return spring pair, there is on my 1969 truck with Quadrajet.

71Ochre · 01-03-2017, 10:59 PM

I have a return spring on the drivers side and a divorced choke coil spring on the passenger. I did replace both of those.

geezer#99 · 01-03-2017, 11:01 PM

Take a pic of both sides of your carb.
Otherwise it's just a guessing game.

71Ochre · 01-03-2017, 11:17 PM

OK here is each side.

geezer#99 · 01-03-2017, 11:30 PM

Try turning down the high idle.
It's a phillips head screw right under the choke vacuum pot.

71Ochre · 01-03-2017, 11:32 PM

OK I think I saw that today. I will try that tomorrow. Thanks.

**Stocker** · 01-03-2017, 11:35 PM

Maybe this will help https://www.youtube.com/watch?v=qmFCh8LhRrU

geezer#99 · 01-03-2017, 11:37 PM

And your kickdown cable is on the wrong hole. It needs to be where your spring is. And your spring goes where you have the kickdown.
Then your spring will work better.

**LockDoc** · 01-04-2017, 12:26 PM

-
Yup, no tension on the return spring....

LockDoc

67ChevyRedneck · 01-04-2017, 01:01 PM

Are you letting it warm up and it's still doing it? That's how carbed vehicles warm up, they have a choke/fast idle, it can take a few minutes when it's cold for the idle to drop to normal.

**Wrenchbender Ret** · 01-04-2017, 05:00 PM

What part of town are you in? If you can't get it worked out, I might be able to stop by & take a look at it.
George

demian5 · 01-04-2017, 05:09 PM

Quote:

Originally Posted by 71Ochre

OK here is each side.

Whats up with the vacuum hose going between manifold and ported vacuum over the fuel inlet?

trucks72 · 01-04-2017, 05:52 PM

I think his kick down cable is in the right spot. His spring is just to long to give any tension. Just needs a shorter spring.

jkeady · 01-04-2017, 11:46 PM

Quote:

Originally Posted by demian5

Whats up with the vacuum hose going between manifold and ported vacuum over the fuel inlet?

Yeah, I agree- I can't quite tell from the photos but if you ARE connecting your ported and manifold vacuum ports on the front of the carb... that's going to be a problem.

01-03-2017, 10:11 PM	#1
71Ochre Registered User Join Date: Jan 2017 Location: Kansas City Posts: 8	New Carb will only accelerate New here, just posted in the welcome section. I have a 71 C10 with a 350 and a Rochester Quadrajet. I have installed a new carb and when I start up the truck it just accelerates and the pressure rises. Any ideas?

01-03-2017, 10:50 PM	#2
Wrenchbender Ret Registered User Join Date: Oct 2005 Location: Overland Park, Ks. Posts: 5,190	Re: New Carb will only accelerate If you mean the engine just races & won't return to idle, It could be the linkage needs adjusting or the secondary throttles are not closed.

01-03-2017, 10:52 PM	#3
71Ochre Registered User Join Date: Jan 2017 Location: Kansas City Posts: 8	Re: New Carb will only accelerate I am new to carbs. I looked over all of the linkages but not sure what would need adjusted.

01-03-2017, 10:57 PM	#4
dmjlambert Senior Member Join Date: Apr 2016 Location: Cypress, TX Posts: 3,575	Re: New Carb will only accelerate I think there should be a return spring pair, there is on my 1969 truck with Quadrajet.

01-03-2017, 10:59 PM	#5
71Ochre Registered User Join Date: Jan 2017 Location: Kansas City Posts: 8	Re: New Carb will only accelerate I have a return spring on the drivers side and a divorced choke coil spring on the passenger. I did replace both of those.

01-03-2017, 11:01 PM	#6
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,516	Re: New Carb will only accelerate Take a pic of both sides of your carb. Otherwise it's just a guessing game.

01-03-2017, 11:17 PM	#7
71Ochre Registered User Join Date: Jan 2017 Location: Kansas City Posts: 8	Re: New Carb will only accelerate OK here is each side. Attached Images

01-03-2017, 11:30 PM	#8
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,516	Re: New Carb will only accelerate Try turning down the high idle. It's a phillips head screw right under the choke vacuum pot.

01-03-2017, 11:32 PM	#9
71Ochre Registered User Join Date: Jan 2017 Location: Kansas City Posts: 8	Re: New Carb will only accelerate OK I think I saw that today. I will try that tomorrow. Thanks.

01-03-2017, 11:35 PM	#10
Stocker 20' Daredevil (Ret) Join Date: May 2003 Location: Jefferson State Posts: 13,499	Re: New Carb will only accelerate Maybe this will help https://www.youtube.com/watch?v=qmFCh8LhRrU __________________ - Mike - 1972 K20 LWB 350/350/205 RIP El Jay

01-03-2017, 11:37 PM	#11
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,516	Re: New Carb will only accelerate And your kickdown cable is on the wrong hole. It needs to be where your spring is. And your spring goes where you have the kickdown. Then your spring will work better.

01-04-2017, 12:26 PM	#12
LockDoc The Older Generation Join Date: Aug 2006 Location: Montezuma, Iowa Posts: 25,332	Re: New Carb will only accelerate - Yup, no tension on the return spring.... LockDoc __________________ Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 -

01-04-2017, 01:01 PM	#13
67ChevyRedneck Hittin E-Z Street on Mud Tires Join Date: Nov 2004 Location: Greenville, SC Posts: 23,090	Re: New Carb will only accelerate Are you letting it warm up and it's still doing it? That's how carbed vehicles warm up, they have a choke/fast idle, it can take a few minutes when it's cold for the idle to drop to normal. __________________ Jesse James 1967 C10 SWB Stepside: 350/700R4/3.73 1965 Ford Mustang: 289/T5-5spd/3.25 Trac-Loc 1968 Pontiac Firebird: Project Fire Chicken! 2015 Silverado Double Cab 5.3L Z71 2001 Jeep Wrangler Sport 4.0L 5spd 2020 Chevrolet Equinox Premium 2.0L Turbo 2011 Mustang V6 ~ Wife's ride American Born, Country by the Grace of God 1967 CST Shop Truck Rebuild! My 1967 C-10 Build Thread My Vintage Air A/C Install Project "On a Dime" Trying my hand at Home Renovation! 1965 Mustang Modifications!

01-04-2017, 05:00 PM	#14
Wrenchbender Ret Registered User Join Date: Oct 2005 Location: Overland Park, Ks. Posts: 5,190	Re: New Carb will only accelerate What part of town are you in? If you can't get it worked out, I might be able to stop by & take a look at it. George

01-04-2017, 05:52 PM	#16
trucks72 trucks72 Join Date: Jul 2002 Location: Crossville Posts: 315	Re: New Carb will only accelerate I think his kick down cable is in the right spot. His spring is just to long to give any tension. Just needs a shorter spring.



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