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Carburetor Questions

Okay well **** rebuilding it, I want to just buy a Holley or Edelbrock. Do I need one with an electric choke or a manual choke? If I got one with a manual choke, I would have to run a choke cable to the inside of the truck, correct?

Also, what CFM does this carb come stock, so I can get the right CFM carb when I buy a new one.

And last but not least, how should I go about tuning it? Sorry for the newb questions guys, but try to help me out. Thanks.
 
yeah you'd have to run a cable but i haven't yet this summer and have had no problems. more of a winter thing. i'd get the manual myself cause i've had better luck with those.
i'm running the 600 CFM Edelbrock and couldn't be happier. go any more than that you'll have problems.
i tuned mine but it varies on motors. turned both screws all the way in and turned round 2 whole turns out and just adjusted from there. actually think i went in to like 1 3/4 0r 1 1/2 turns out. just adjust em out to where it's idling good and when you open it up there is no hesistation. other people may have a different opinion on this
 
Yeah, I hear many different opinions on this subject, which is why I'm afraid to buy a new carb. What does the Q-Jet have? Doesn't it have an "auto-choke"?

I just want one I can slap on there and tune a bit, and be fine with. But it's never that easy.
 
nad said:
Yeah, I hear many different opinions on this subject, which is why I'm afraid to buy a new carb. What does the Q-Jet have? Doesn't it have an "auto-choke"?

I just want one I can slap on there and tune a bit, and be fine with. But it's never that easy.
Click to expand...

Most were automatic (i.e. didn't require any input from you) but Q-jets used a ton of different choke styles. Realize that they were on GM cars and trucks from the 60's into the early 90's.

I would recommend an electric choke. Manual chokes suck.
 
But will an electric choke carb work just like my auto choke Q-jet? Or would it actually need wiring?

I'm stuck here and don't know what I should do. Rebuild mine, even though I already messed up some stuff on it, or just buy a rebuilt Q-jet. Or buy a Holley or something.
 
nad said:
But will an electric choke carb work just like my auto choke Q-jet? Or would it actually need wiring?

I'm stuck here and don't know what I should do. Rebuild mine, even though I already messed up some stuff on it, or just buy a rebuilt Q-jet. Or buy a Holley or something.
Click to expand...

Well, Holleys are easier to tune and work with. They are a simpler design.

The electric choke will need a little wiring done but its very simple and nothing you should be afraid of.
 
What CFM should I get? Will the electric choke use any wires on my stock wiring harness, since I still have the wiring harness from my TBI setup?
 
None of the wiring is the same. If you get a real case of the A$$, they make plates to bolt and injector to a carb intake. That's how mine is set up and works great, no leaks.

Back to the carb, a qjet is 750 cfm unless it came off a big block. There is a book by Doug Roe about rochester carbs (also applies to carter built qjets). Make sure the float is set how it specs. Honestly never had a problem using the qjet. Always ran better and used less fuel.

Also never bought a new carb that I didn't have to rejet and tune, so you are back to the same tuning issue. MAke sure your timing is right...
 
nad said:
What CFM should I get? Will the electric choke use any wires on my stock wiring harness, since I still have the wiring harness from my TBI setup?
Click to expand...

600 CFM is the right size for a stock 350.

As for the wiring, it won't be plug and go. You will have to splice into some wiring that's already there. I'm guessing the choke will have 2 or 3 wires: one for ground, one for power (the directions that come with it will suggest some good places to find a switched 12V power source) and maybe a wire to tap into the temp sender wire. Really, its about as easy as it gets for wiring something new in.
 
nad said:
What CFM should I get? Will the electric choke use any wires on my stock wiring harness, since I still have the wiring harness from my TBI setup?
Click to expand...
I agree with others, 600cfm for an Edelbrock / Holley type carb. Electric choke is easy on the Edelbrock, just 2 wires... One is ground of course, and that's easily wired by putting one end of the wire under the head of the nearest small screw. The alternator body is close enough--that's how I did it. So that wire is only like 15" long. The hot wire just needs to be connected to a switched 12V source (you don't need power to the choke when the truck's off!). There's a bunch under the hood so finding one shouldn't be a problem.

I'd tell you which wire to use, but mine's an '86 carb'd model, not TBI. I'd take this opportunity to get a factory wiring manual for your truck and learn to read it. It's invaluable.

Just be glad that you didn't catch the motor on fire and burn up the harness. When I replaced it, I had to learn everything the hard way with no pics to guide me :crazy::crazy::crazy: The wiring manual saved me.

BTW, I will be switching back to a newly rebuilt Q-Jet after I rebuild one of mine. They're good carbs and I already have 2 options for the choke--electric and hot water.
 
if you plan on wheeling, stick with the q-jet. i've never had mine die on me offroad. i'm not even careful about angles. if i feel like driving up or down something, i do. actually, i'm more concerned about the oil sloshing away from the oil pump or up into the cylinders than i am about flooding or leaning the q-jet.

i did a manual choke conversion not long ago. nice.
 
Well I can't figure out how my carb is an auto choke, but has no wiring to it whatsoever.

What would you guys think about just buying this one that's been professionally rebuilt?

http://cgi.ebay.com/ebaymotors/Rebu...014QQitemZ330139053730QQrdZ1QQsspagenameZWD1V

The problem is, I broke one of the little needles in half. And lost a spring from mine while trying to rebuild it. It's just a lot of trouble to do when I don't have a work bench or anything, so I had to do it in my driveway.

Should I just go to a junkyard and buy another carb like this and use the parts from it? Or just go for a fully rebuilt one and use it?
 
nad said:
Well I can't figure out how my carb is an auto choke, but has no wiring to it whatsoever.
Click to expand...

By "auto choke" I assume you mean, anything that's not manually controlled by a cable. There's electric and there's also a water-heated "auto" choke. I have a Q-Jet with the water setup on it. I never used it, but the guy I got it from used it for years with no problems. It didn't require wiring, just a small hose plumbed into the cooling system. As the engine warms up, it heats up the coolant, and the choke opens. Simple.

I'm probably going to go with that setup for simplicity when I re-do some stuff on the engine.
 
That's exactly what this one does. Opens as the engine warms up. But there's no wiring.
 
I guess I'm gonna just run to the junkyard and get the parts I need for my carb and finish rebuilding it. If it still runs like crap, I'll just buy a professionally rebuilt Q-jet and have someone that knows what they're doing tune it. Thanks for the advice guys, and keep it coming ;) Thanks again.
 
nad said:
Well I can't figure out how my carb is an auto choke, but has no wiring to it whatsoever.

What would you guys think about just buying this one that's been professionally rebuilt?

http://cgi.ebay.com/ebaymotors/Rebuilt-Quadrajet-17058213-Chevy-Carburetor-Carb_W0QQcmdZViewItemQQcategoryZ33550QQihZ014QQitemZ330139053730QQrdZ1QQsspagenameZWD1V

The problem is, I broke one of the little needles in half. And lost a spring from mine while trying to rebuild it. It's just a lot of trouble to do when I don't have a work bench or anything, so I had to do it in my driveway.

Should I just go to a junkyard and buy another carb like this and use the parts from it? Or just go for a fully rebuilt one and use it?
Click to expand...

The only needles I can think of in the carb are the metering rods. If you are going to replace them, you need to get the same ones that were in there or you will be changing the mixture. They have a little number stamped on the side of them like "36B".

IIRC there are only a few springs on a Q-jet: two for the accelerator pump (bigger ones) and one for the power piston (smaller). The power piston springs vary too, and changing them affects part throttle performance.

Edelbrock sells new metering rods and power piston springs for cheap. It may be worth your while to just get new ones :dunno:
 
Possibly. I believe I'm also missing the cover screw for the pump discharge ball. I don't remember ever taking one out, and I never took the ball out either, but now I can't figure it out. Also, the lock ring for the choke rod, doing it in my driveway I had everything laying on newspaper, and the wind blew and that thing disappeared.
 
My choke is controlled by a little spring-like whatchamacallit that sits on a little pad on the passenger side of the manifold.
The pad heats up, heats the spring, spring expands, and it opens the choke plate.
If the pad is cold, the spring is coiled more tightly, and it pulls the choke plate closed.
I dont have it hooked up right now, because when I put the carb spacer in, the linkage wasnt long enough.
No cables, no wires.
 
Kp said:
My choke is controlled by a little spring-like whatchamacallit that sits on a little pad on the passenger side of the manifold.
The pad heats up, heats the spring, spring expands, and it opens the choke plate.
If the pad is cold, the spring is coiled more tightly, and it pulls the choke plate closed.
I dont have it hooked up right now, because when I put the carb spacer in, the linkage wasnt long enough.
No cables, no wires.
Click to expand...
i had this setup. liked it for a little while til i got an Edelbrock for cheap
 
Kp said:
My choke is controlled by a little spring-like whatchamacallit that sits on a little pad on the passenger side of the manifold.
The pad heats up, heats the spring, spring expands, and it opens the choke plate.
If the pad is cold, the spring is coiled more tightly, and it pulls the choke plate closed.
I dont have it hooked up right now, because when I put the carb spacer in, the linkage wasnt long enough.
No cables, no wires.
Click to expand...

Thats a divorced choke... On just about every carbed boat for 20 yrs... pretty foolproof...
 
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