Hey guys, I'm trying to get my truck ready to go to TN in June. I have a 600 CFM Carter AFB on a 305 Chevy. I KNOW it's too rich right now and I'm goin to buy a tuning kit for it. The problem (or maybe not) is that I cant find a kit for a "Carter" and it looks identical to an Edelbrock so I bought a kit for the Edelbrock 600 CFM. First do you think they are the same? The salesman at Jegs said they were. Second I know the metering rods come out the top and I can do it right on the truck to just change the metering rods, but how are they measured or rated? A buddy said to go to the next biggest size rod since it would fill out the jet and make it tighter and let in less fuel. I know that's right, but I need to know how they are measured and rated?

I'd love to get better than 10mpg's but most of all I dont want to ruin my engine by making it too lean. I know it's better to be too rich than too lean so any of you carb gurus please help!!!

 

the Carter AFB and the Edelbrock do use the same metering rods, but I can't really tell which direction to go.

 

There was a book that came with my Edelbrock carb tuning kit that explained the carb operation and the tuning methods really well. The metering rod sizes and the spring weights were listed and color coded. If you don't have the book, get it. Mine came from my local hot rod shop that sold me the kit.

 

Terry, whats the problem that makes you say you KNOW it's running rich? Plug condition? Black smoke out pipes? Rough idle? Edelbrock.com - Performance Carburetors, Cylinder Heads, Intake Manifolds, EFI Systems, Fuel Pumps, Crate Motors has an FAQ on such things. Metering rods included, I think. The guys at the Edelbrock booth at the NSRA Nats told me not to mess with mine. (1406)

 

exactly my thoughts. are you going to mess with the primary jets or secondarys? your carb is a 600cfm so you think it's too big and rich? MAYBE at WOT but just cruise in the primaries it"s like have a real small 2 barrel on it.

 

The Edelbrock website says specifically their jets and rods are "not for use with other brands of carburetors". Since I can't believe anyone would try to use metering rods on a Holley, I have to assume they mean Carter. You might try lowering your existing needles a notch or two, then playing with float level.

 

All of the above. It has black smoke out the pipes and STINKS of fuel. The plugs are a little black, but not fouled. I just want to lean it out a little.

 

Quadra Junks use metering rods. As for lowering needles there's no way to do that, unless the springs have something to do with the height? I'm no carb expert by no means, I just want to not make it worse.

Thanks guys!!

 

OK then my first response is way off. so what's it do at idle? That's using a different "circuitry" (if you will) so if it still flooding then maybe your dealing with float level as mentioned before.
I'm just goin off my experience with a mild 292/312 Y-block and a Edelbrock 600cfm that's producing perfect looking plugs.(even though all the calculations will say it's too much fuel) You might be off on the jet size theory.

 

Ok i looked up the beast your dealling with and I think it's your float.



Try this site for some info

Carter AFB/AVS - The Carburetor Doctor

 

I went through the same thing. I used the Edelbrock website as a reference. Their diagram for tuning the carb is pretty confusing. Like Randy Jack mentioned, the kits usually show you what rods and springs to use to lean the mixture. First, you have find out where your carb is at. What meter rods you have and what springs you are using. Then you can go to a leaner metering rods and a shorter spring which will lean the mixture. If that doesn't work, you may need to pull the top of the carb and check the size on your jetting. Your calibration kit will also come with jets. I had .98 in mine and went to a .95 in my primaries. That leaned my carb quite a bit. Edelbrocks and Carter's love to run at a lean mixture. You'll see a big improvement in gas mileage and performance if you lean up the carb. With you blowing black smoke and fumes out the rear, my guess is you may want switch out the jets. Be advised, when you make too much of lean mixture it can effect you mid range and WOT (wide open throttle) performance. You need to try different combination. Start with the metering rods and springs, and then go for the jets. Make sure you clean the plugs after the adjustment, go for a ride and then check the color of the plugs. They should be a light gray color. After each change, you have to readjust your idle mixture screws. Adjust them to the point you have the highest idle. Then I back them out about half turn. BTW- my Edelbrock worked with Carter metering rods too.

 

Thanks very much guys I ordered the calibration kit yesterday from Jegs. Last night I took out the metering rods and they have a number stamped in them. The number is 7147 The jet has 120 stamped on the top of it on one part and 400 stamped on the bottom of it? Anyone know what these numbers mean? I also have red colored springs on the metering rods.


I wont know too much more til I get my kit on Monday. But maybe some of you guys will know what these numbers mean? Thanks again!!!!

 

Thanks very much for the site, but my computer wont let me see the info. I dont have Adobe Reader I guess I'll have to wait for my kit and see what I have??

 

Terry,
The 7147 metering rod is the standard metering rod for the 600 CFM. The springs you are using are the standard also. The 7047 rod is slightly richer and that's what I'm running in mine with the same springs you have. I think you problem is the jetting. 120 and .400 are the sizes. .400 is pretty big for the 600 CFM. I've got some head work and porting done and I'm running .398 in the primary and .395 in the secondary. (I could still lean out my carb) I had the .400 and .398 in my carb and it barely ran. Poor idle, etc. (not to mention drinking gas) Your definitely going to have to change out the jets. Try the .395 and .398 and see what that does. You might be fine with the metering rods and springs you have now. Those jets are definitely too big. Let me know how it goes.

 

Thank you so much Imlowr2. Thats what I needed to hear someone who knows the numbers. You say the 400 is the size? You dont think I'll need to change the rods and springs? Of course this is all kind of futile til I get my kit on Monday, but I like to know.

On a side note, I dont know if this makes sense or not? But, when it's kind of cool outside it runs better. Like I said I get crummy gas mileage, and I thought it was cause its so under powered and heavy? I have 3:25 gears and 29 1/2" tires. I know its never goin to get great mileage and dont expect miracles, but more than 10mpg's would be NICE!

Thanks again for your time and patience. I was hoping to not have to take the top off and change the jets, but................. I guess I'll have to?