Help! Carburetor on 250 I-6

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DoubleDingo

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I agree with @Bextreme04 on the choke rod, but I think finding one bent specifically for that carb would be better suited than just bending something to make it work.
 

JohnTaurus

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The issue with how it is right now, is that the choke is always on. There is no bracket or other things to get. All you need to do is bend some welding wire on it so that when that spring on the manifold heats up it lifts your choke lever up to open the choke and let it off the high idle cam. The reason it started fine in the winter is because your choke is ALWAYS on right now. The reason you can't kick it down off the high idle cam is because that lever isn't getting lifted to let it happen. You need to either hook it up, or strap it in the OFF position all the way up. That will make it harder to start when cold, but will keep you from driving around with the choke on and on the fast idle cam.

I understand, and I will do that. Thank you again.
 

JohnTaurus

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That alone should make a big difference. :favorites13:

Oh it has! I drove it around some this evening, it is far more manageable lol, not the chore it was before. I didn't realize how bad it was until now. He was appalled at the dinky way it was setup. That was the theme for the morning with every thing he worked on, lol.

And, I'd love a beer, lol. Wish I could buy all of us a couple of rounds!
 

mmanter

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I came across your post, and had to read it all. Sounds like a fun project you have converting to EFI and OD. My 82 C10 has a 250. It's different. Not what you find every day. And I like that about it.
 

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I came across your post, and had to read it all. Sounds like a fun project you have converting to EFI and OD. My 82 C10 has a 250. It's different. Not what you find every day. And I like that about it.

Thanks! I love my old truck, and I have been a fan of Inline 6s since I've seen what they can do. And, there's the being different part, but it's not just for that reason. I do enjoy having something unique, and it's just an awesome old engine that has withstood crap that would've killed 8 Toyotas by now! LOL

Here's a pic of the new little breather element on the side of the valve cover. I would've preferred a gold bowtie, but it's fine like it is, haha!

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mmanter

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That’s really sharp. I heard what the six can do, and even though my trucks original six is long gone I want to keep the 250. It has a good sound, decent pickup, and heard it can haul with more torque. I upgraded mine to a 2 barrel. I heard they can give a little more pep. I eventually will install a Holley 2 barrel EFI unit. Original GM parts are hard to come by at local salvage yards.
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JohnTaurus

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That looks amazing! I wanted my valve cover orange, but I found the chrome one for what I could afford, so that's what I got.

Great looking engine bay man!
 

mmanter

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That looks amazing! I wanted my valve cover orange, but I found the chrome one for what I could afford, so that's what I got.

Great looking engine bay man!
Thanks! I repainted it black, since that was the original color. Eventually I will repaint the engine. Can’t wait to drive the truck more.


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JohnTaurus

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The issue with how it is right now, is that the choke is always on.

The reason you can't kick it down off the high idle cam is because that lever isn't getting lifted to let it happen. You need to either hook it up, or strap it in the OFF position all the way up. That will make it harder to start when cold, but will keep you from driving around with the choke on and on the fast idle cam.

With all due respect, I think you're mistaken, and it may be due to misinformation, or miscommunication by myself. For that, I apologize.

The choke is not on. It is not doing the high idle anymore because the linkage isn't being held (sometimes) by a mis-routed return spring. That issue is completely fixed.

The "kickdown" simply freed the spring from where it was catching. I could demonstrate this under the hood by manually moving the throttle bracket where the cable attaches. If I slowly moved the throttle up and then eased off, it stayed there. If I manipulated the linkage or cable or bracket in any way, it would go back to resting idle. If I raced the engine and let go as I did it, it went to its resting position without sticking. This was what the "kickdown" (stabbing the throttle one time) did.

I kept thinking this was the cable or linkage, so I replaced the cable and oiled the joints of the linkage. This helped, but only slightly.

I tell you how sensitive it was: sometimes, I could stick my foot under the edge of the pedal and lift it up, and just that tiny release of tension would be enough to let it go down. It didn't work every time.

The butterfly valve (choke) is in the up (open) position all the time. There is nothing to move it closed.

The truck behaved like a typical cold-natured carbureted vehicle when starting in the cold, but it wasn't bad. I would have to hold the throttle at a high RPM (1700-2000) for 20-30 seconds, then it was good to go. That's what I meant by "starting fine". It was about average for the carburetor vehicles I've had in the past. That's one of the many times I wish for EFI.

If need be, I can remove the air cleaner and take pictures. I may be mostly ignorant about carburetors, but I would know that if that butterfly valve was staying closed, that it would cause problems.

Again, I apologize, as I'm sure it was my miscommunication, my mistake in some fashion, was was at fault, here. I do appreciate your help, and everyone else's as well!
 

Bextreme04

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With all due respect, I think you're mistaken, and it may be due to misinformation, or miscommunication by myself. For that, I apologize.

The choke is not on. It is not doing the high idle anymore because the linkage isn't being held (sometimes) by a mis-routed return spring. That issue is completely fixed.

The "kickdown" simply freed the spring from where it was catching. I could demonstrate this under the hood by manually moving the throttle bracket where the cable attaches. If I slowly moved the throttle up and then eased off, it stayed there. If I manipulated the linkage or cable or bracket in any way, it would go back to resting idle. If I raced the engine and let go as I did it, it went to its resting position without sticking. This was what the "kickdown" (stabbing the throttle one time) did.

I kept thinking this was the cable or linkage, so I replaced the cable and oiled the joints of the linkage. This helped, but only slightly.

I tell you how sensitive it was: sometimes, I could stick my foot under the edge of the pedal and lift it up, and just that tiny release of tension would be enough to let it go down. It didn't work every time.

The butterfly valve (choke) is in the up (open) position all the time. There is nothing to move it closed.

The truck behaved like a typical cold-natured carbureted vehicle when starting in the cold, but it wasn't bad. I would have to hold the throttle at a high RPM (1700-2000) for 20-30 seconds, then it was good to go. That's what I meant by "starting fine". It was about average for the carburetor vehicles I've had in the past. That's one of the many times I wish for EFI.

If need be, I can remove the air cleaner and take pictures. I may be mostly ignorant about carburetors, but I would know that if that butterfly valve was staying closed, that it would cause problems.

Again, I apologize, as I'm sure it was my miscommunication, my mistake in some fashion, was was at fault, here. I do appreciate your help, and everyone else's as well!

Ah, ok. Yeah the behavior you were describing was exactly what my 4-bbl quadrajet with the same choke setup did when the rod came disconnected. I was assuming the single carb on yours had the same high idle cam, just on the other side of the carburetor that we can't see in your pictures. Is there nothing connected to the choke rod on the throttle side?

I would recommend at least wiring the flapper open so that it doesn't flap over and randomly choke the engine as you are driving around. If there is nothing holding the choke flap open it could flap closed while driving and make it intermittently run super rich.
 

JohnTaurus

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Ah, ok. Yeah the behavior you were describing was exactly what my 4-bbl quadrajet with the same choke setup did when the rod came disconnected. I was assuming the single carb on yours had the same high idle cam, just on the other side of the carburetor that we can't see in your pictures. Is there nothing connected to the choke rod on the throttle side?

I would recommend at least wiring the flapper open so that it doesn't flap over and randomly choke the engine as you are driving around. If there is nothing holding the choke flap open it could flap closed while driving and make it intermittently run super rich.

I'm sorry, I totally spaced replying here. I thought I had, I do apologize.

I have continued to update my other thread "My 1974 C10", link: https://www.gmsquarebody.com/threads/my-1974-c10.29048/page-3

There is nothing connected to the linkage to the choke that I can find anywhere.

The carburetor was rebuilt since the last time I updated this thread, and its livable for now. It's just a junk carburetor from new, and I'd invest in a better one if I wasn't planning an EFI upgrade. These issues have more than turned the tide away from my continuing to use carburetors when the intake and head are replaced. Haha
 

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