Stalls when pressing gas too fast

[73c20jim]

x2

 

[thecantaloupeman]

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]

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

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[thecantaloupeman]

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

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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?

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[TravisB]

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]

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.

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[Chevyguy]

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.

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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

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[thecantaloupeman]

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

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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]

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

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Quadrajet base

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[Nonstop]

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]

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]

Should be able to reference the number on your unit.

 

[thecantaloupeman]

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.

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[1987 GMC Jimmy]

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]

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?

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