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Full Version: Weber 44IDF Idle settings?
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CptTripps
My idle sits at about 2500rpm, and that is a little too hight for my taste. So I'm off to do my first carburator adjustment. I did some searching, and came up with this procedure...anyone have anything to add?? I was going to drop the optical ignition in too, but I think I should stick to one thing at a time. (for once)

:::: Found at http://www.carburetion.com/Weber/adjust.htm ::::

SET UP ADJUSTMENTS

Start set up by confirming carb base line settings. Do not depend on the factory delivered settings. Check them before the carb is installed.

1. All settings are done with choke disengaged or warmed up so that the choke is fully opened and disengaged. This is done on automatic choke carburetors by first opening the choke butterfly by hand and inserting a wood block or wedge of some kind to hold open while the linkage is cycled (linkage operated through its full movement) to clear the choke cam. (You will hear a metallic click as the cam is released. You can check the fast Idle screw under the choke assembly to confirm that it is not in contact with the choke fast idle cam.)

2. Set the Idle stop screw (speed screw see fig 1) by backing out the Idle speed screw until it is not in contact with the throttle stop lever. Cycle the linkage again to be sure that the linkage comes to close without any assistance. (Checking for linkage bind) Now bring screw back into contact with the lever and continue to open or screwing in 1 turn no more than 11/2 turns.

3. Set the mixture screw (see Fig 1) by first screwing in until the screw stops, bottoms out. DO NOT FORCE OR BIND AS THIS WILL CAUSE DAMAGE TO THE SCREW AND IT’S SEAT IN THE BODY OF CARBURETOR. Back out the screw 2 full turns.

4. TUNING

BE SURE TO FOLLOW THE NEXT INSTRUCTIONS IN THE PROPER SEQUENCE, DEVIATION WILL CAUSE THE CARBURETOR TO NOT FUNCTION TO ITS IDEAL SPECIFICATIONS AND MAY NOT PROVIDE THE PERFORMANCE AND FUEL ECONOMY AS DESIGNED.

4a. Start the engine, the engine will run very slowly more like a tractor. As long as the engine stays running idle speed is not important at this point.

4b. The first thing to do is not set up the idle speed, but to set the idle mixture screw to lean best idle setting. First, turn in the mixture screw until the engine dies or runs worse, then back out the screw (recommend turning ¼ to ½ turn at a time). The engine should pick up speed and begin to smooth out. Back out ½ turn more, or until the screw does nothing or runs worse then turn back to the point where it ran its best. Use your ear, not a scope or tuning instruments at this point. You want to tune the engine by sound. Adjust to best, fastest and smoothest running point.

4c. Now that the mixture screw is at its best running location, you can adjust the idle speed the screw. The screw will be sensitive and should only take ¼ to ½ turns to achieve the idle speed you like.
Check and set idle to your driving preference. Put the car in gear and apply slight load, (AC on) and set the Idle as you like it. Don’t set it too high, as this will cause causes excessive clutch and brake wear. The Idle only needs to be 7 to 900 RPM with light load or AC on.

5. Recheck timing and vacuum hook ups. Recheck mixture screw to lean best idle again. If all is still best and smoothest idle then confirm and note the final settings.

To confirm settings with the engine running. Start by screwing in the mixture screw and count the number of turns it takes to bottom out and note if the engine dies. If Idle Mixture screws are with in ½ turn of base line setting then all is well and have fun. Also check the speed screw and note how many total turns from initial contact. You may have opened (turned in) the speed screw. Your final setting should be under 2 full turns. Reset the screws (back in) to the best final settings (Per your notes) and go on a test drive and have fun. If the settings are other than described then you may want to recalibrate the idle circuit (low speed circuit) to your engines needs. This is done by following the rule of thumb BELOW.

Simple Rules for low speed calibration

If the mixture screw is more than 2 1/2 turns out turns then the idle jet is too lean (too small). When the mixture screw is less than 11/2 then the Idle jet is too rich (too large). These assumptions are based on the fact that the speed screw setting is not opened more than 11/2 turns. If the speed screw has to be opened 2 or more turns then this is also an indication of a lean condition usually requiring greater change. At times it may appear to be showing signs of richness or flooding it is really a lean condition. See pictures and notes in the tech 2 article supplied in the kit instructions, view and please understand the need to keep throttle plate as near to closed as possible so as not to prematurely expose the transition holes. This is what causes the visible rich condition, and confirms the need to increase the jet size. JET KITS are available if needed.

EXAMPLE With the speed screw set at no more than two (2) turns in after contact with the stop lever; and the best idle occurring with the mixture screw set at 3 turns from bottom, indicates the need for a larger Idle jet. Achieving the best idle at under 2 turns indicates the need for a smaller idle jet.

The secret to understanding the critical nature of the carburetor set up and the advantages of a WEBER over other carburetors is the idle circuit. Referred to as the low speed circuit by Weber, this circuit is responsible for 80% of the driving operation. This is the reason that the Weber should give a fuel economy improvement over most factory carbs along with significant performance gains. In the worst case you should not see a significant fuel economy loss over stock, while improving HP & Drivability.

The Weber Carburetor is a sequentially timed device to the motor like the distributor. Time taken in the setup will provide more fun later.

If you should need to call REDLINE WEBER for technical assistance we will need to know your final settings to help. Technical assistance is free for the first 60 days of purchase. Units in service over 60 days may be assessed a service fee. All charges will be noted up front after a brief consultation to determine any possible defect. If the carb is out of the warranty period and no defect is determined we will estimate the possible cost of tech support or recommend literature available that may help.
rhodyguy
too much. here's a pretty simple method. there are 2 idle adjustment screws. back one off its stop (i back off the pass side). this lets one of the carbs follow the idle as determined by the threaded rod connected to the linkage. use the other idle screw to adjust the idle speed. now would be the time to check for equal flow for both carbs. with the "working" screw turn the idle up so the "pulsing" on your syncronizing tool subsides. use the "free" threaded rod to bring the carbs to equal flow, then turn the idle back down with the "working" screw to 900 rpm or so. at times it's a bit of back and forth, but pretty straight forward. when you get them the flowing same, run the "free" screw back in to the point where the idle just starts to climb. now move on to the idle air mixture needle screws. aircooled.net has a good carb tech article and the cb weber book has a v.g. trouble shooting guide.

k
SGB
Dual Webers, right?
The instructions you show are correct, but kinda generic regarding choke, etc. It DOES NOT address carb balance. Hopefully, the carbs are balanced, just idle is too high. So you will have what Redline calls the "speed screw" on each carb. Warm the car up to operating temp. Back one speed screw out all the way (passenger side maybe) and then adjust to about 1000 rpm using the similar screw on the other (drivers side) carb. If you can get to the right idle doing this, then your golden. Ya might wanna bring the passenger side screw up so it is just touching the throttle arm too and try backing the drivers side out 1/16 turn just to even up the stresses on the carb linkage. If the idle is still high (I am assuming timing is correct or of course it will cause the idle to be really high) then you should prolly loosen the locknuts on the "air bypass screws". There are two one each carb at the base, next to the "mixture volume screws" (your instructions just say mixture screws) which are a little bigger, knurled screws with springs on 'em After the locknuts are loose on those air bypass screws, turn each in 1/2 turn, tighten locknuts, and try again. (you can do this with engine running too to see if you can percieve a diff) What you are doing here is reducing air going in at low RPM past those air-bypass screws- if you reduce too far, you'lkl get black smoke (too rich): Try to get those down within 1 or two turns from the bottom, tighten up, and then start messing with the "mixture volume screws" turning in one one barrel at a time until the idle drops, the engine sputters, or the exhuast starts to POP POP POP, then turn back out about 1/2 turn or the engine idle cleans up. Go around doing each carb barrel individually. It seems to change around as you mess with the other cylinders, so you may wanna do this twice. If nothing slows down the idle, I thinki your timing advance is prolly too high and if you don't reduce it you will fry something....
CptTripps
So what is the right idle RPM setting?

On the way to work I noticed a few things...

#1 - It idles at about 1300-1500 SOME TIMES. I have to go by the tach at the light without the car in gear.

#2 - Other times (stoplights) it is at 2200-2500. If I put it in gear, and ease off the clutch to slow the motor down, sometimes it stays...other times, it creeps back up again.

Maybe I'm looking at the wrong thing???

Other things to note...

I've got Dual Weber 44IDF carbs - 6" stacks - 2.0 motor w/euro lifters.

I'm taking a 800mi trip this weekend, so I want to make sure everything is AOK before I leave the driveway.
Joe Ricard
Hey Captain Try this. What you got is both carbs fighting each other via the linkage.

Disconnect the drivers side reach rod from the pivot arm. Now set the flow of right and lef carb with uni-syn. You will be turning idle stop screws a little bit on both carbs. Concentrate on bringing the higher flowing carb down to the lower flowing carb. Should idle about 900. Least mine do. Now you can double check the idle jet metering screws. Should have had them 1 1/2 turns out all the same to begin with.

once you get them equal you will see that the linkage reach rod don't match anymore. lossen jam nuts and adjust then re connect.

DON'T MESS with idle stops NO MORE

Now you need to still get the carbs perfectly synched to open at the same rate. What I do is take some tension on the throttle cable to run @ 1200 RPM the idle stops should now be off the stop screws.

This is where you adjust the length of the reach rod to get the linkage to operate both carbs the same.

release tension on the throttle cable and engine should return to 900 1000 RPM.

THAT's HOW YOU SYNCH CARBS.
CptTripps
That sounds more like what I need to do...thanks Joe.

I'm going to eave the office around 3:30 today and go attack this thing. I'll see what I have after that. I'm also driving out to a book store I found that has a Weber Carb book. Can't hurt to have one of those...right?

SGB
Make sure you check your timing. It sounds like it is too high and you donwanna run 800 milesw like that....
rhodyguy
sustained, calm idle at 950. why would you want to disconnect a rod? you need to avoid the stand off of one side or another. start with no bind. oh, you need a quality linkage to set things up by my method.

k
Joe Ricard
"No bind" is not close enough to keep the carbs exactly the same as the throttle is opened. the last step is about a 1/2 degree of rotation on the read rod one way or the other. Makes a significant difference in smooth off idle performance.
BTW my linkage is about as rock soild as they come. not sure of the manufacture. Think it is a mutt of CB and something else.
Tom Perso
To set your idle, you HAVE to have the linkage disconnected. Get it set, then base your linkage arms off of that. I usually get the idle set, then run the carbs dry (disconnect the fuel pump, as she starts to sputter, start working the throttles to clean out the last bit in the carbs).

With the carbs dry, you can hook up the linkage, adjust it, and work the throttle as many times as needed without flooding the motor.

Once you're set, hook the pump back up, let it refill the bowls, and go give it the Italian tune up.

Done

Tom
CptTripps
Ok...we were ALL wrong!

The spring that pulls the throttle back to the 'closed' position was disconnected at one end.

Re-attched it...I'm hovering at 1000-1100 now. wink.gif
Joe Ricard
Nope not wrong. Linkage should be tight enough that there is NO SLOP between carbs. the spring thing is not fixing the problem just covering it up.
Plus you didn't post pics so I couldn't SEE THAT rolleyes.gif
Glad you are getting a handle on it.
Just by chance take a little extra slack out of your cable and throw that uni-syn gauge on em. Question is are they both equal when pulled off the idle stops? If yes THEN you got it fixed GUD.
CptTripps
I'll post pics in a few min. Maybe someone can draw over them and tell me what is what so I kjnow what I'm adjusting!
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