1406 edelbrock problem - The 1947 - Present Chevrolet & GMC Truck Message Board Network

tino0217 · 01-20-2021, 01:51 AM

I have a 71 C10 with a 350 small block Edelbrock 1406 carburetor I have disconnected the auto choke a couple of months ago and recently I've noticed that the idols been kind of high. I tried to adjust the idle screw with no response the idle does not change. I've adjusted the air and gas mixture but still no change I sprayed carburetor cleaner in it and it's still idling high. Things that I've read that there might be some debris stuck inside there that's causing some type of blockage. If this is true would that be the effect that the carburetor would have no response to the adjustment that I've done on the idle screw and the air and gas mixture?

SkidmoreGarage · 01-20-2021, 03:45 AM

I'm not a carb expert, but I have rebuilt a 1406.

I would look for any air leaks (vacuum leaks) after the throttle blades. This could be that the carb mounting nuts have loosened, the gasket has failed (backfire blew it out), or there is a loose fitting in the carb/vacuum lines, or intake manifold.

It could be a lot more complicated than that, but high idle and poor control are usually signs that air is getting in to the engine from somewhere. Usually fuel issues cause the car to not want to idle.

RustyPile · 01-20-2021, 08:14 AM

If the curb idle screw adjustments have no effect on idle speed, I suspect the fast idle cam is "locked" in the engaged position.. Probably caused when you "disconnected the choke". The idle mixture screws have no effect because the throttle is open enough so that the engine is actually running on the transfer circuit...

Prop the choke blade in the fully open position.. This will allow the fast idle cam to drop down away from the fast idle screw... The question begs to be asked ---- Why (and how) did you disconnect the choke??

hugger6933 · 01-20-2021, 08:29 AM

My first thought was the high idle cam had flipped. check to make sure the carb isn't "thinking" that the choke is closed. If that doesnt work, get out the carb cleaner and spray around the base of the carb, the intake sealing areas and so forth to see if the carb cleaner will find a bad gasket. you will know if you have found the problem, see when you spray carb cleaner around the area that has a leak, the idle will go even higher. Jim

68 P.O.S. · 01-20-2021, 12:02 PM

What's your timing set at?

01-20-2021, 01:51 AM	#1
tino0217 Registered User Join Date: May 2017 Location: Seatac, wa Posts: 172	1406 edelbrock problem I have a 71 C10 with a 350 small block Edelbrock 1406 carburetor I have disconnected the auto choke a couple of months ago and recently I've noticed that the idols been kind of high. I tried to adjust the idle screw with no response the idle does not change. I've adjusted the air and gas mixture but still no change I sprayed carburetor cleaner in it and it's still idling high. Things that I've read that there might be some debris stuck inside there that's causing some type of blockage. If this is true would that be the effect that the carburetor would have no response to the adjustment that I've done on the idle screw and the air and gas mixture?

01-20-2021, 03:45 AM	#2
SkidmoreGarage Registered User Join Date: Mar 2020 Location: Portland, OR Posts: 335	Re: 1406 edelbrock problem I'm not a carb expert, but I have rebuilt a 1406. I would look for any air leaks (vacuum leaks) after the throttle blades. This could be that the carb mounting nuts have loosened, the gasket has failed (backfire blew it out), or there is a loose fitting in the carb/vacuum lines, or intake manifold. It could be a lot more complicated than that, but high idle and poor control are usually signs that air is getting in to the engine from somewhere. Usually fuel issues cause the car to not want to idle.

01-20-2021, 08:14 AM	#3
RustyPile Registered User Join Date: Dec 2017 Location: Elkhart, Texas Posts: 1,526	Re: 1406 edelbrock problem If the curb idle screw adjustments have no effect on idle speed, I suspect the fast idle cam is "locked" in the engaged position.. Probably caused when you "disconnected the choke". The idle mixture screws have no effect because the throttle is open enough so that the engine is actually running on the transfer circuit... Prop the choke blade in the fully open position.. This will allow the fast idle cam to drop down away from the fast idle screw... The question begs to be asked ---- Why (and how) did you disconnect the choke??

01-20-2021, 08:29 AM	#4
hugger6933 Registered User Join Date: Oct 2008 Location: Marianna Arkansas Posts: 7,257	Re: 1406 edelbrock problem My first thought was the high idle cam had flipped. check to make sure the carb isn't "thinking" that the choke is closed. If that doesnt work, get out the carb cleaner and spray around the base of the carb, the intake sealing areas and so forth to see if the carb cleaner will find a bad gasket. you will know if you have found the problem, see when you spray carb cleaner around the area that has a leak, the idle will go even higher. Jim

01-20-2021, 12:02 PM	#5
68 P.O.S. Registered User Join Date: Jan 2007 Location: Puyallup, WA Posts: 1,661	Re: 1406 edelbrock problem What's your timing set at? __________________ 72 C10 lwb fleetside -stock 350/350 combo



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