Stalls when pressing gas too fast

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

73c20jim

Full Access Member
Joined
Jun 11, 2018
Posts
2,282
Reaction score
2,924
Location
Tombstone, AZ
First Name
Jim
Truck Year
1973, 1973
Truck Model
C20 2WD Custom Deluxe. C10 2WD Base Model
Engine Size
350 CID 195/260 HP Goodwrench crate, 400 CID 2bbl
x2
 

thecantaloupeman

Full Access Member
Joined
May 14, 2019
Posts
447
Reaction score
144
Location
US
First Name
Dawson
Truck Year
1978
Truck Model
C20 Silverado Camper Special
Engine Size
350
If you were closer I'd put you to work. Troubleshoot your truck, and I've got plenty here you can learn on
That would be pretty awesome! Wish I knew someone who was closer to me I could do this with.
 

Chevyguy

Full Access Member
Joined
Sep 10, 2012
Posts
185
Reaction score
60
Location
Eugene,OR
First Name
Clayton
Truck Year
1987
Truck Model
V20
Engine Size
5.7 Litre
When you rebuild your carburator also replace the float. The old ones wear out and get cracks, or pinholes in them from the fuel.

Clayton

Sent from my LM-V350 using Tapatalk
 

thecantaloupeman

Full Access Member
Joined
May 14, 2019
Posts
447
Reaction score
144
Location
US
First Name
Dawson
Truck Year
1978
Truck Model
C20 Silverado Camper Special
Engine Size
350
When you rebuild your carburator also replace the float. The old ones wear out and get cracks, or pinholes in them from the fuel.

Clayton

Sent from my LM-V350 using Tapatalk
xc_hide_links_from_guests_guests_error_hide_media
Could someone check this series out and let me know if it's a decent representation of what I'll need to do? I figure this video and that book should be a good resource right?

Sent from my SM-G950U using Tapatalk
 

TravisB

Full Access Member
Joined
Jan 3, 2018
Posts
1,087
Reaction score
1,071
Location
Kentucky
First Name
Travis
Truck Year
1978
Truck Model
C10
Engine Size
350
I am sure someone has already said so but this is probably your accelerator pump. If your ignition is all right like your spark advance and stuff I am betting that is the only thing it could be. Maybe a huge vacuum leak but I doubt it. You can pretty easily check all three of those if you have eyes, a timing light, and a can of carb cleaner or flammable brake clean.
 

thecantaloupeman

Full Access Member
Joined
May 14, 2019
Posts
447
Reaction score
144
Location
US
First Name
Dawson
Truck Year
1978
Truck Model
C20 Silverado Camper Special
Engine Size
350
Honestly, if this is your only transportation, I would consider slapping on a used carb from the junkyard or from a friend and make the truck safe to drive for now. Take the one that is on there and have it professionally rebuilt.

I respect that you want to learn and I am seeing the questions you are asking and eagerly learning. If this is your only mode of transportation, it is a pain in the ass if you replace the accelerator pump, do not put it back together right, and have to take it off and take it apart a few times. Quadrajets can be intimidating, as can any carb at this level for you. Again, not knocking you in any way, simply speaking from having been young and learning as I went.

Once this is rebuilt, take the used one off and tear into it and use that one to learn on.
I called up the junkyard and they have a presumably used holley speed demon for 300 bucks. That's about as much as a rebuild. I called up a pretty good local carb shop and it was 285. I don't know, would that be something to consider? If not, new edelbrocks are about 300 new.

Also they did tell me that carbs at their yard are 38 bucks so I might consider looking for a 4 bbl q-jet or just another 4bbl carb and just try to rebuild my carb myself. That way I could slap the used one on while I have my q-jet off and then I'd be able to still drive the truck.

Sent from my SM-G950U using Tapatalk
 

Chevyguy

Full Access Member
Joined
Sep 10, 2012
Posts
185
Reaction score
60
Location
Eugene,OR
First Name
Clayton
Truck Year
1987
Truck Model
V20
Engine Size
5.7 Litre
I called up the junkyard and they have a presumably used holley speed demon for 300 bucks. That's about as much as a rebuild. I called up a pretty good local carb shop and it was 285. I don't know, would that be something to consider? If not, new edelbrocks are about 300 new.

Also they did tell me that carbs at their yard are 38 bucks so I might consider looking for a 4 bbl q-jet or just another 4bbl carb and just try to rebuild my carb myself. That way I could slap the used one on while I have my q-jet off and then I'd be able to still drive the truck.

Sent from my SM-G950U using Tapatalk
Does the carb shop have a one already that's ready to go. All you might have to do is swap out the throttle linkage.

Clayton

Sent from my LM-V350 using Tapatalk
 

thecantaloupeman

Full Access Member
Joined
May 14, 2019
Posts
447
Reaction score
144
Location
US
First Name
Dawson
Truck Year
1978
Truck Model
C20 Silverado Camper Special
Engine Size
350
Does the carb shop have a one already that's ready to go. All you might have to do is swap out the throttle linkage.

Clayton

Sent from my LM-V350 using Tapatalk
Well I don't know much about that speed demon. It must be rebuilt or something because hes got it for sale at the counter for 300$. The yard typically charges 38 bucks for carbs off cars in the yard if you pull it yourself. I have no idea if a holley speed demon would work with my engine or not. My guess is that it wouldn't. How do i determine what carbs will fit on my engine and work well with it?
 

Craig 85

Full Access Member
Joined
Jan 25, 2017
Posts
3,889
Reaction score
4,024
Location
Nashville, TN
First Name
Craig
Truck Year
1985
Truck Model
K30 SRW
Engine Size
454/TH-400/NP205
You would have to run adapter with the stock intake and modify things to switch to a Holley. Holley's usually have a square bore base, Quadrajets are spread bores. I know your young, but rebuilding a carb is not hard. I did mine in about a day. If you watch the videos it's pretty easy. I did my first one pre-internet.

Holley base
You must be registered for see images attach


Quadrajet base
You must be registered for see images attach
 

Nonstop

Full Access Member
Joined
Nov 16, 2014
Posts
775
Reaction score
2,417
Location
Ca
First Name
Nick
Truck Year
1985
Truck Model
K2500
Engine Size
454
Pluck a $38 carb off a car in the yard and call it a day. Right now just get it running right. Go in there, find the cleanest carb and buy it. Bolt it on. If it runs like ****, bring it back for another.

At this point, I would not screw with the Speed Demon, Holley, or any other. The right Quadrajet will literally be plug and play. Any of the aftermarket ones will need to be adapted.

Get the book, get a quality kit, and rebuild the one on the truck while you have the junkyard carb on there.
 

thecantaloupeman

Full Access Member
Joined
May 14, 2019
Posts
447
Reaction score
144
Location
US
First Name
Dawson
Truck Year
1978
Truck Model
C20 Silverado Camper Special
Engine Size
350
Pluck a $38 carb off a car in the yard and call it a day. Right now just get it running right. Go in there, find the cleanest carb and buy it. Bolt it on. If it runs like ****, bring it back for another.

At this point, I would not screw with the Speed Demon, Holley, or any other. The right Quadrajet will literally be plug and play. Any of the aftermarket ones will need to be adapted.

Get the book, get a quality kit, and rebuild the one on the truck while you have the junkyard carb on there.
How can I make sure I get the right quadrajet? Is it mainly just looking for the same/similar year and same throttle linkage?
 

TerryRH

Full Access Member
Joined
Mar 28, 2019
Posts
477
Reaction score
906
Location
Jacksonville, NC
First Name
Terry
Truck Year
1987
Truck Model
R10
Engine Size
350ci
Should be able to reference the number on your unit.
 

thecantaloupeman

Full Access Member
Joined
May 14, 2019
Posts
447
Reaction score
144
Location
US
First Name
Dawson
Truck Year
1978
Truck Model
C20 Silverado Camper Special
Engine Size
350
Should be able to reference the number on your unit.
What are the odds? I just found a free quadrajet listed on craigslist. It's in a hell of a state, but If i rebuild that one I've got nothing to lose. If I successfully rebuild it, I can just plop it onto my truck and possibly rebuild the other one too. I might be able to sell one of them for a profit or something. How do I tell if this one will work with my truck though? It says its from an 88 van that had a 5.8L engine. The fuel filter assembly on the front is different but the rest of it looks fairly similar. I am not able to see the carb number from the pics.

You must be registered for see images attach


You must be registered for see images attach
 

1987 GMC Jimmy

Automobile Hoarder
Joined
Jan 23, 2016
Posts
5,848
Reaction score
2,387
Location
Mississippi
First Name
Jesse
Truck Year
1987
Truck Model
V1500 Jimmy
Engine Size
350
Yeah, this one’s a front inlet not a side inlet. This one’s got an electric choke, and yours is divorced. That should be it. The electric choke is nice when it’s done right (oil pressure safety switch in the circuit). That way if your ignition sits on for a moment, the choke heater isn’t running away, and then you end up flooding it because you didn’t start it up right away, and the choke opened while it was still cold. I’ve only ever seen front inlet Quads in BOP applications and therefore side inlets on Chevies and GMCs. They do make a banjo fitting to adapt it so you could theoretically use your molded steel line with no issue. I’d rather the one that’s on there to not have to mess with the choke setup, but this is probably the next best thing.
 

thecantaloupeman

Full Access Member
Joined
May 14, 2019
Posts
447
Reaction score
144
Location
US
First Name
Dawson
Truck Year
1978
Truck Model
C20 Silverado Camper Special
Engine Size
350
Yeah, this one’s a front inlet not a side inlet. This one’s got an electric choke, and yours is divorced. That should be it. The electric choke is nice when it’s done right (oil pressure safety switch in the circuit). That way if your ignition sits on for a moment, the choke heater isn’t running away, and then you end up flooding it because you didn’t start it up right away, and the choke opened while it was still cold. I’ve only ever seen front inlet Quads in BOP applications and therefore side inlets on Chevies and GMCs. They do make a banjo fitting to adapt it so you could theoretically use your molded steel line with no issue. I’d rather the one that’s on there to not have to mess with the choke setup, but this is probably the next best thing.
So i got to thinking. I went out to look at my carb and was wondering if it's possible to remove the air horn without taking the carb off the car. I might just be able to replace the accelerator pump and be done. I inspected the carb more and it does look fairly clean on the outside. It would be a lot less stressful if I were able to just disconnect a few things, pop the air horn off and replace the part, then just put it all back together.

It looks like maybe these three things are all I need to disconnect. Am I right?
You must be registered for see images attach
You must be registered for see images attach
You must be registered for see images attach


Sent from my SM-G950U using Tapatalk
 

Forum statistics

Threads
41,851
Posts
903,510
Members
33,365
Latest member
rossivey
Top