Truck won't stay running - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Squareforceone · 08-02-2015, 01:07 PM

I replace the carb and intake on my 350 with an edelbrock performer rpm intake and a BRAND NEW street demon carb. Now I can't get the truck to run. It'll fire and start if you keep revving it it'll stay running but as soon as you let off it'll die. It's not the choke or anything like that. I thought maybe there was a vacuum leak. I don't know where it could be. All the vacuum ports on the carb are plugged. I have the vaccum advance unhooked and the ports sealed off. I just can't figure it out. Im not sure of the timing right now i thought maybe it was 180 out so I pulled the distributor out and reinstalled it. I've tried turning the distributor all over the place.

77 Big 10 · 08-02-2015, 02:10 PM

Did you try adjusting the idle circuit? Maybe the adjustment screws are in too far, if so try 3 turns out from full closed then when idling you can do the idle tune procedure.

Squareforceone · 08-02-2015, 04:37 PM

yes not 3 turns but I did adjust the mixture screws some and the curb idle screw no change..

77 Big 10 · 08-02-2015, 05:20 PM

If it was a tooth off it would run poorly, but if I read it right, the idle is the problem. If you are sure the manifold sealed, and all the vacuum ports are plugged on the front of the carb, the vacuum port on the manifold is plugged, or vacuum lines are hooked up to it, and they are not leaking? Second, the large vacuum line from the back of the carb for the brake booster, etc, is hooked up and also not leaking? I'd say an internal vacuum problem with the carb.

08-02-2015, 01:07 PM	#1
Squareforceone Registered User Join Date: Nov 2010 Location: Rustville USA or southeast Ia Posts: 654	Truck won't stay running I replace the carb and intake on my 350 with an edelbrock performer rpm intake and a BRAND NEW street demon carb. Now I can't get the truck to run. It'll fire and start if you keep revving it it'll stay running but as soon as you let off it'll die. It's not the choke or anything like that. I thought maybe there was a vacuum leak. I don't know where it could be. All the vacuum ports on the carb are plugged. I have the vaccum advance unhooked and the ports sealed off. I just can't figure it out. Im not sure of the timing right now i thought maybe it was 180 out so I pulled the distributor out and reinstalled it. I've tried turning the distributor all over the place. __________________ Rust is better than rice.

08-02-2015, 02:10 PM	#2
77 Big 10 Registered User Join Date: Jul 2015 Location: La Quinta, CA. Posts: 131	Re: Truck won't stay running Did you try adjusting the idle circuit? Maybe the adjustment screws are in too far, if so try 3 turns out from full closed then when idling you can do the idle tune procedure.

08-02-2015, 04:37 PM	#3
Squareforceone Registered User Join Date: Nov 2010 Location: Rustville USA or southeast Ia Posts: 654	Re: Truck won't stay running yes not 3 turns but I did adjust the mixture screws some and the curb idle screw no change.. __________________ Rust is better than rice.

08-02-2015, 05:20 PM	#4
77 Big 10 Registered User Join Date: Jul 2015 Location: La Quinta, CA. Posts: 131	Re: Truck won't stay running If it was a tooth off it would run poorly, but if I read it right, the idle is the problem. If you are sure the manifold sealed, and all the vacuum ports are plugged on the front of the carb, the vacuum port on the manifold is plugged, or vacuum lines are hooked up to it, and they are not leaking? Second, the large vacuum line from the back of the carb for the brake booster, etc, is hooked up and also not leaking? I'd say an internal vacuum problem with the carb.



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