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JonOfScio

the quick weber tuning guide.

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Here's the quick way to tune a DFxV/DGxV carburetor. (DFAV 28/32, DGEV 32/36, Holley 5200)

 

With the car off, warmed up if possible, if not, have the choke fully open.

 

Turn the mixture screw all the way in. Don't force it. once it stops, it's done stopped! Back it out 2 turns.

 

Turn the idle screw out until it no longer touches the linkage. turn it back in until it just barely makes contact. Turn it 1.5 more times.

 

these are base settings for tuning a weber carburetor. From here, turn the car on.

 

Slowly turn the idle up, and then back down. Find the spot that it just barely will idle at. Then turn it in about 1/4" or until it's the smoothest running.

 

Adjust the mixture screw by turning it in or out. (in = lean, out = rich)

 

Adjust it until you feel you have the best position for smoothness in the idle. if you find that it is out more than 2.5 turns, you may want to consider putting in smaller jets. If you find that it is less than 1.5 turns, you may consider putting in bigger jets.

 

Once you feel comfortable with the running conditions from there, go back to adjusting the idle. Go as low as you can before it starts to die. if you have a/c, turn it on. You want it to idle about 700-900 RPM with full load accessories. All this info on listening is really good for those (like caboobaroo) who don't have tachs! If you feel comfortable with what you think your mileage should be, the way it responds, and if the number of turns matches about what is reccomended for everything, Great. if not, then you might want to consider adjusting internal parts. (idle, mains, air adj.)

 

all this info can be found on weber's website..... http://www.redlineweber.com

 

go to technical documents and there will be all the tuning info for their various carbs. The most important piece is the base line settings... if you don't know that, you can'd accurately tune the carb.

 

Hope this helps.

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That is the absolutely correct procedure. However, I have a small clarification to add. As you say, the one jet you might consider changing is the primary idle jet; this is an air bleed jet and the comments about which way to go if rich or lean are correct in your description. However, playing with the other jets will not do you much good. The weber is a fairly simple carb. Everything below 3000 rpm is governed by the primary idle jet and the mixture screw. Playing with the air bleed jets and/or main jets isn't something you can do without the proper equipment to monitor air/fuel ratio at various rpms. The secondary idle jet's main purpose in life is to ease the transition when the secondary opens up around 3500 rpm. I've learned a bit over the last two weeks about the weber and I'm still trying to get mine to pass emissions but this guide will help get you close if not right on; depends how good an "ear" you have for tuning.

 

 

Here's the quick way to tune a DFxV/DGxV carburetor. (DFAV 28/32, DGEV 32/36, Holley 5200)

 

With the car off, warmed up if possible, if not, have the choke fully open.

 

Turn the mixture screw all the way in. Don't force it. once it stops, it's done stopped! Back it out 2 turns.

 

Turn the idle screw out until it no longer touches the linkage. turn it back in until it just barely makes contact. Turn it 1.5 more times.

 

these are base settings for tuning a weber carburetor. From here, turn the car on.

 

Slowly turn the idle up, and then back down. Find the spot that it just barely will idle at. Then turn it in about 1/4" or until it's the smoothest running.

 

Adjust the mixture screw by turning it in or out. (in = lean, out = rich)

 

Adjust it until you feel you have the best position for smoothness in the idle. if you find that it is out more than 2.5 turns, you may want to consider putting in smaller jets. If you find that it is less than 1.5 turns, you may consider putting in bigger jets.

 

Once you feel comfortable with the running conditions from there, go back to adjusting the idle. Go as low as you can before it starts to die. if you have a/c, turn it on. You want it to idle about 700-900 RPM with full load accessories. All this info on listening is really good for those (like caboobaroo) who don't have tachs! If you feel comfortable with what you think your mileage should be, the way it responds, and if the number of turns matches about what is reccomended for everything, Great. if not, then you might want to consider adjusting internal parts. (idle, mains, air adj.)

 

all this info can be found on weber's website..... www.redlineweber.com

 

go to technical documents and there will be all the tuning info for their various carbs. The most important piece is the base line settings... if you don't know that, you can'd accurately tune the carb.

 

Hope this helps.

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