View Full Version : Issue with Carb?

07-14-2008, 10:44 PM
I have a 56 transtar with I belive a 289 v8 not exactly sure on the motor because my grandfather repacled the original V8 with what I belive is a commander engine. anyway, it has a Stromberg WW
(2 barrel).

The issue is the motor will idle fine but when you open the throttle plates it cuts out and usually dies. Sometimes you can close them in time and it will stumblee to idle. But if you are real slow on the throttle it will rev fine. Also i'm not all thay good with carbs but i have the basic idea and I am a young Mechanic so I am somewhat competent.

I have already replaced the accelerator pump and put in new carb gaskets. But no change. I also don't see any vacumn leaks.

Last time I messed with it I noticed that there wasn't any fuel coming out of the "main jets" if thats what they are called.

Any help would be greatly appreciated.

Also I think I read a Rochester 2GC fits the same bolt pattern. Are all 2GC's the same will one from a firebird work? Also are there any other redilly available Carbs that fit the mainfold?

Thank you in advance

07-14-2008, 11:04 PM
Sounds like the fuel nozzles are clogged..if this carb even has them. Do you feel a lot of resistance when you depress the accel pump by itself?

07-14-2008, 11:08 PM
I havn't tried to depress the accel pump arm alone prehaps I shall try that tommorrow and I have been thinking about blowing some carb clean back through the fuel ports.

07-14-2008, 11:19 PM
Sounds like a bad accelerator pump. See if you are getting a squirt.

"I'm a great believer in luck and I find the harder I work, the more I have of it."
Thomas Jefferson

07-15-2008, 02:54 AM
Be sure to check for a vacuum leak. See if its sucking air from the throttle shafts or perhaps the gasket at the base. Also check the hoses at the pcv. You can do this with a can of WD 40 and just spray in all areas where a leak may occur. You will hear a momentary change in idle rpm if there is a leak.


Dwain G.
07-15-2008, 11:19 AM
There should be two check balls in the accelerator pump circuit. If they are stuck, missing, or not seating well this allows the circuit to go dry, or lose its prime. The larger of the two valves sits in the bottom of the accelerator pump well. The other one is below the injector nozzles.

Dwain G.

07-15-2008, 06:57 PM
May I suggest advancing the timing a little and check to see if the vacuum advance canister holds vacuum. A bad accel pump circuit would cause a stumble but if everything else is right it doesn't usually get bad enough to cause the engine to stall.

You won't see fuel coming out of the venturis at idle unless it's set way too high.



07-15-2008, 09:41 PM
Your right you shouldn't see fuel at idle but when you crack the throttle you should!!

BTW. It's Fixed

Thanks Buddymander you were right, I blew carb clean back through the nozzles, unhooked accel pump and it was pretty stiff about 1/2 way through travel. On the third or fourth pump I felt the clog flush out!!!! Now I just have to reset the mixtures and it's good to go.

07-16-2008, 09:39 PM
Glad I could help.