Help me tune my edelbrock carb (I lack the vocabulary)

[DissFigured]

I downloaded the manuel, and have read a lot online, and I have learned that i seriously lack the vocabulary to do a lot of this. I am smart enough to look at most things and rebuild/fix etc, but the carb is not intuitive. I am a software engineer and I have the same problem w/ my wotrk. I can program circles around most folks, but I have no idea why you should never dereference a NULL pointer in C++.

Kidding aside:
I have the 4 barrel edelbrock performer. 289

Currently, I have idle set high because it was dying on me. However I think it is too rich because I am getting a lot of liquid (Gas?) coming out of my tailpipes. This is a total guess based on my expierence w/ model airplanes.

I can't figure out what all I need to do to start tuning this thing from scratch. I know 2 screws on front seem to be key. I close em off and I can make it die but not sure which is which and where to start and what to listen for. Also, I appear to have an electric choke. I have know idea what it does and turning it seems to have no effect. What is it's purpose?

so, any tips on any of this as if you were explaining it to your mom would be great.

 

[dbfarr]

Get a vacuum or rpm gauge.

The liquid is water, a natural by product of combustion.

Until then, with the engine off turn the screws at the bottom (Idle air screws) all the way in. Then back them both out 1 1/2 turns.

Start the car up, let it warm up.

If it still runs like cacaa, then you have problems elsewhere...

Like, choke adjustment, timing chain slack, vacuum leak, etc.

Anyway, do this and post back.

 

[jikelly]

I bumped all of the posts I could find using the search for my previous posts. The most in depth carter/edelbrock carb tunning guide is a dead link now, which sucks cuz it was a good thread.

I'll write up another for you. I've personally rebuilt the carter and edelbrock carbs at least ten times over the last ten years. They are pretty easy to rebuild and tune for outstanding performance (in my opinion they are a better carb than the holley style, but that's just my opinion and not anything scientific).

If you've seen the manual than you know how it goes together, and what parts are involved. Mainly right now you should be concerned with your idle circuit, well and your choke setting. you can look in that manual for the base choke setting and set your carb there. The choke effects when, and how far your throttle blades open after the heating element in the electric choke warms up, and to a surprising degree your part throttle drivebility.

You wanna get a vacuum gauge as suggested, use a vacuum line to hook it up to a vacuum source on your manifold and it will help you tune your carb's idle circuit.

1. "with the engine off turn the screws at the bottom (Idle air screws) all the way in. Then back them both out 1 1/2 turns."

2. Start the engine and allow it to warm up.

3. Hook up vacuum gauge

4. Check your vacuum gauge to see if it is getting a reading (mine would usually be around 9-11lb)

5. Adjust your idle mixture screws by turning each of them an equal amount (you ideally want the two mixture controls at the same setting. You will hear, smell and, thanks to the vacuum gauge, see the effect this has on your engine.

6. As you adjust the mixture towards the perfect air/fuel ratio you engine vacuum will increase. Past that point the vacuum level will fall. So, you want to play with it till the mixture screw setting gives you the highest vacuum reading on the gauge.

Other considerations are your engine idles speed, which I'm pretty certain you will have to decrease once you get your mixture optimized, and your choke setting which is definitely going to affect your idle mixture. I generally set my choke one to two ticks past the central point mark, and my idle speed/Rpm at 700-800 RPM.

Good Luck!!

 

[D.Hearne]

I thought Edelbrock carbs didn't need tuning?

 

[jikelly]

I never said they didn't need tunning, in fact they need a lot and frequent cleaning if you live in a dust bowl like Lubbock, I just said they were easy to tune.

 

[DissFigured]

Thanks,

This sounds like what I needed.

Off to get a vacuum gage.

 

[iskwezm]

also make sure there is no vac. leaks. You might have to buy a assortment of metering rods to get it tuned.

 

[dbfarr]

http://www.telusplanet.net/public/gilesij/Volvord/edelbrock_1.htm

The most complete Edelbrock carb tuning guide I have ever seen. He even includes an extensive on jet metering rod combos

http://www.telusplanet.net/public/gilesij/Volvord/carb_jet.htm

Ford 302 in a 750 Volvo...

Anyway,...

 

[jikelly]

Bump

 

[jtfairlane]

Edelbrock has a bunch of videos on tuning their carbs, why don't you go check those out:

http://www.edelbrock.com/automotive_new/misc/tech_center/install/tech_vids.shtml

 

[JDS68Stang]

Try the suggestions that were given so far. If you still aren't sure what your doing
take the car to a GOOD mechanic that knows his stuff and have him finish it up for you. He might need to keep the car till it's cold and start w/ the choke adjustment first. Ask the mechanic if you can have him explain the process as he's doing it so you'll know from then on what does what on the carb. You want your car in optimum performance mode regardless who gets it to that point. If you leave your car overnight at a shop, make sure they put it INSIDE overnight so it will still be there the next day.

You remind me of my brother, he's not a lawyer, but in Family or County Court he'd run circles around the best attorneys our area has to offer and made them look like total fools more than once. Appeals he has written out and finished in a day or so and he wins, yet he can't read a tape measure and gets totally confused when I try and explain the increments of it, makes no sence. Good luck on the carb.