Carburetors Carb discussion and questions. Upgrading your Third Gen's carburetor, swapping TBI to carburetor, or TPI to carburetor? Need LG4 or H.O. info? Post it here.

Clogged Carb

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Old Dec 13, 2019 | 01:03 PM
  #1  
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Clogged Carb

84Z H/O and i have an electronic carburetor, the passenger side primary is not squirting any fuel. The driver side though, anyone know of anyway to clear out the carb with it on the car? or anyway to blow out the passages? Thank you.
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Old Dec 13, 2019 | 02:09 PM
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Re: Clogged Carb

Originally Posted by blaze2fury
84Z H/O and i have an electronic carburetor, the passenger side primary is not squirting any fuel. The driver side though, anyone know of anyway to clear out the carb with it on the car? or anyway to blow out the passages? Thank you.
if quadrajet, can take the top plate off and see if it is clogged in fuel supply to the bowl(bowl will be empty) or past the jets. but if having issues like that, probably better to clean and rebuild.
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Old Dec 13, 2019 | 03:19 PM
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Car: 1986 IROC Z
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Re: Clogged Carb

Originally Posted by blaze2fury
84Z H/O and i have an electronic carburetor, the passenger side primary is not squirting any fuel. The driver side though, anyone know of anyway to clear out the carb with it on the car? or anyway to blow out the passages? Thank you.
If there's an obvious problem with one part of a carburetor, it's almost certain there are other, as yet unseen issues as well. Additionally, trying to partially disassemble a carburetor containing many small parts/screws while it's still on the engine is asking for a potentially-much-more-serious problem when said small parts disappear down an intake passage.


Take the carburetor off the engine, get a kit, and clean/rebuild the entire carb. Good idea to also replace the fuel filter at this time.


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Old Dec 13, 2019 | 08:29 PM
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From: Meriden, CT 06451
Car: 84 TA orig. 305 LG4 "H" E4ME
Engine: 334 SBC - stroked 305 M4ME Q-Jet
Transmission: upgraded 700R4 3200 stall
Axle/Gears: 10bolt 4.10 Posi w Lakewood TA Bars
Re: Clogged Carb

Originally Posted by ironwill
If there's an obvious problem with one part of a carburetor, it's almost certain there are other, as yet unseen issues as well. Additionally, trying to partially disassemble a carburetor containing many small parts/screws while it's still on the engine is asking for a potentially-much-more-serious problem when said small parts disappear down an intake passage.


Take the carburetor off the engine, get a kit, and clean/rebuild the entire carb. Good idea to also replace the fuel filter at this time.

Also. the seals, gaskets. O-rings, etc are probably breaking down because these carbs were built at a time before there was ethanol in the fuel.
Get a kit that has ethanol compatible parts.
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Old Dec 15, 2019 | 02:57 PM
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Re: Clogged Carb

Ok guys I rebuilt the carb, not as hard as I thought it was gonna be. I put it back on and ran it. No leaks and now both primaries are working. But now it's hard to keep the car running. It starts idles for a second or so and then idles down and dies. I upped the idle screw to keep it going but then it was idling way to high so when I turned it down again it was back to idling for a few seconds and then dies. Any ideas? The choke stays open so I'm thinking I have to readjust that? Only thing is I didn't mess with the choke at all during rebuild. The air/fuel mixture screws are both at 3 1/2 to just get it at a beginning start. But other than dying it seems to have full power I just can't keep it running unless I have my foot on the gas. Thanks all.
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Old Dec 15, 2019 | 03:32 PM
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From: Meriden, CT 06451
Car: 84 TA orig. 305 LG4 "H" E4ME
Engine: 334 SBC - stroked 305 M4ME Q-Jet
Transmission: upgraded 700R4 3200 stall
Axle/Gears: 10bolt 4.10 Posi w Lakewood TA Bars
Re: Clogged Carb

Before you start adjusting things, check for vacuum leaks. Those small plastic lines snap easily.
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Old Dec 15, 2019 | 03:46 PM
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Car: 1986 IROC Z
Engine: 5.0 TPI
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Re: Clogged Carb

Originally Posted by NoEmissions84TA
check for vacuum leaks. Those small plastic lines snap easily.
Assuming you have correct fuel pressure at the carb inlet, and you've set the float level to spec, check ^^^^these.

Also, make certain you've used the correct carb-to-manifold base gasket (most kits provide several in order to cover many different applications).
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Old Dec 15, 2019 | 04:54 PM
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From: Meriden, CT 06451
Car: 84 TA orig. 305 LG4 "H" E4ME
Engine: 334 SBC - stroked 305 M4ME Q-Jet
Transmission: upgraded 700R4 3200 stall
Axle/Gears: 10bolt 4.10 Posi w Lakewood TA Bars
Re: Clogged Carb

You beat me to it - base gasket was going to be the next suggestion.
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Old Dec 15, 2019 | 09:57 PM
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Re: Clogged Carb

I watched a carb rebuild video before I did it that someone posted on here and he said leave the float at basic settings would be fine. That I didn't need to bend the metal tab. It's not flooding, so I didn't think it was the float. I matched the base gasket with the old one I took off. Will check that again and the vacuum lines. I don't hear any out of the normal air sucking though. Also no fluctuating idle when I can get her to run for longer than 10 seconds.
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Old Dec 16, 2019 | 05:38 PM
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From: Meriden, CT 06451
Car: 84 TA orig. 305 LG4 "H" E4ME
Engine: 334 SBC - stroked 305 M4ME Q-Jet
Transmission: upgraded 700R4 3200 stall
Axle/Gears: 10bolt 4.10 Posi w Lakewood TA Bars
Re: Clogged Carb

New fuel filter installed correctly?
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Old Dec 16, 2019 | 07:31 PM
  #11  
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Car: 1987 Z28 Camaro
Engine: 305 LG4 4bbl
Transmission: TH700R4
Re: Clogged Carb

Remember that theres 2 halves to this fuel circuit, theres the idle circuit and then theres the power circuit (probably a better name for it but i cbf googling it)

The idle circuit is only applicable at idle, but the second enough vacuum is supplied with enough fuel (primary fuel squirts) the idle circuit is no longer active. I do think that everyone here is on the right track with the vacuum leaks, however something that people often overlook is the idle transfer slot being clogged.

If you take the carb off and turn it upside down and open the primary throttle blades, there are 2 little slots inside the barrel, get a fine guitar string and clear these little holes out, (start with a fine string then move up to a slightly more abraisive steel string or as big as you can get in there).

If these are blocked, youll be able to start the car and keep it running while pumping the throttle. If these little slots are blocked then theres no fuel getting into the idle circuit, so there will be no idle no matter how much you stuff around with the idle mixture screws as they only control the amount of air getting in at idle - not fuel.
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Old Dec 18, 2019 | 06:46 PM
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Re: Clogged Carb

Ok guys I have a guess to what is wrong. During the rebuild process a little green pin fell out somewhere (external) that I didn't see where it fell out. Well I was checking everything you guys have said and it all checked out. But then I realized (feel stupid now) that the primary choke door was wide open. I do some looking and my guess is that the pin goes into the choke mechanism that opens and closes the door. Because behind the choke where the linkages are there are 2 that I think are suppose to move together and that pin is what connects them. Cause the car runs without dying if I hand holding the choke door closed when it's cold. So I'm gonna try to slip that pin back in and see what happens.
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Old Dec 18, 2019 | 06:50 PM
  #13  
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Re: Clogged Carb


this little sucker.
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Old Dec 19, 2019 | 06:33 PM
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From: Meriden, CT 06451
Car: 84 TA orig. 305 LG4 "H" E4ME
Engine: 334 SBC - stroked 305 M4ME Q-Jet
Transmission: upgraded 700R4 3200 stall
Axle/Gears: 10bolt 4.10 Posi w Lakewood TA Bars
Re: Clogged Carb

Nope. I believe that is for the TPS potentiometer.
If your choke plate is flopping in the breeze, then you do not have the linkage rod attached properly down inside the carb.
See this: https://www.thirdgen.org/forums/carb...ml#post6225279

Last edited by NoEmissions84TA; Dec 19, 2019 at 06:56 PM.
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Old Dec 20, 2019 | 08:00 AM
  #15  
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Car: 1987 SC/1985 TA
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Transmission: T56
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Re: Clogged Carb

yep

TPS rod. goes under the lever that actuates the booster pump. air horn must come off to install unless one drills out the rivets.

issue sounds choke related to me.
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Old Dec 21, 2019 | 11:50 AM
  #16  
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Re: Clogged Carb

I would of had no idea.. I havnt been able to mess with it for a couple days but today I can. So, if I take the air horn off where does that pin go? Sorry I'm not sure what lever. I know where the TPS is but would have no Idea where to put this pin. And the chokes not loose. It's just straight up. So I will have to adjust the choke. Thank you guys for all the info.
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Old Dec 21, 2019 | 02:54 PM
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From: Meriden, CT 06451
Car: 84 TA orig. 305 LG4 "H" E4ME
Engine: 334 SBC - stroked 305 M4ME Q-Jet
Transmission: upgraded 700R4 3200 stall
Axle/Gears: 10bolt 4.10 Posi w Lakewood TA Bars
Re: Clogged Carb



It's all in this post: https://www.thirdgen.org/forums/carb...ml#post6345058
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Old Dec 21, 2019 | 05:17 PM
  #18  
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Re: Clogged Carb

Does it really do anything? Should I bother putting it back in? What will happen if I don't?
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Old Dec 21, 2019 | 06:37 PM
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From: Meriden, CT 06451
Car: 84 TA orig. 305 LG4 "H" E4ME
Engine: 334 SBC - stroked 305 M4ME Q-Jet
Transmission: upgraded 700R4 3200 stall
Axle/Gears: 10bolt 4.10 Posi w Lakewood TA Bars
Re: Clogged Carb

The ECM will not get the correct info regarding the throttle position.
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Old Dec 22, 2019 | 11:30 AM
  #20  
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Car: 1987 SC/1985 TA
Engine: 350/vortec/fitech
Transmission: T56
Axle/Gears: 3.27 9-bolt
Re: Clogged Carb

put it back in. the car will 'run' without it but with a host of issues to include poor throttle response, loss of mileage and performance and annoying converter lock up issues
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