weber carb help?

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dlb
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weber carb help?

Post by dlb »

i've got a weber 32/36 carb on my 86 terc. it ran great until my dad messed with both the timing and the carb, and now i'm trying to set it back up again but am having problems. does anyone else on here have experience tuning a 32/36? if someone does then i'll list the problems i'm having now. thanks!
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Re: weber carb help?

Post by Snax »

First of all, disconnect the vacuum advance if it is not already, then set the timing to 15 degrees at idle. (On my car, that is pegged to full advance adjustment.) That's what Weber recommends and it seems to work pretty well on mine.

These carbs really are pretty simple, but it all starts with a good idle mixture. Be sure the motor is fully warmed up to obtain the most consistent non-stalling setting.

Assuming he didn't fiddle with the floats and they are set correctly, first try to get a smooth idle by adjusting the idle speed set screw. The key is in getting a smooth idle. Don't worry about how fast it is idling at first. Adjust it lean by turning it in until the motor starts to miss, then back it out about 1/2 turn. Likewise, if all it is doing is missing, back out the mixture about a 1/2 turn past the point where it idles smoothly. Reduce your idle set speed to your desired rpm and go back to tweaking the idle mixture if necessary to eliminate misfiring.

You should be able to get a decent tune messing only with these two settings. If not, you may have to check out other potential issues like fuel pressure or float levels. I've noticed that my throttle linkage got sticky when I let my car sit for six months, so make sure everything on the carb operates smoothly as well, allowing everything move back fully when the throttle is closed. (WD40 works well for fixing that.)
83 SR5, 32/36 Weber DGEV
94 Escort LX Wagon
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dlb
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Re: weber carb help?

Post by dlb »

thanks man, i appreciate it! i have a few more questions for you now though.

where is the vacuum advance? i've seen it mentioned on this forum a few times but i'm pretty new to messing around with engines so if you could even just describe what it looks like to me that would be perfect.

i think my timing is good, it's turned counter clockwise as much as possible, which i presume is advanced. i've set the mixture, idle, and fast idle and what i'm finding is that the fast idle is good (about 1800 rpm), idle is usually good (800 rpm), but after driving for about 20-25 minutes it starts to idle erratically. sometimes it idles at 600, and sometimes it will bounce between 600 and 800. also, a few times while driving i've felt the engine stutter and miss a little bit. does this sound like a vacuum leak? i imagine it is but don't know why it would only happen when it gets really good and warmed up.

another weber question: what does adjusting the choke do? i know that to adjust it i just loosen the 3 screws and rotate the plastic cover but don't know what turning it each direction does. does it change the temperature when the choke disengages?

thanks again!
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Re: weber carb help?

Post by sdoan »

The vacuum advance is the little metal cans attached to the ignition distributor. There are 2 flying saucer shaped can attached together each with at least one vacuum hose going to it. Inside the cans is a rubber diaphragm that vacuum pulls on. The center of the diaphragm is attached to an arm that moves the insides of the distributor to advance the ignition timing. The faster the engine revs the more timing advance you need.

Kieth wrote a nice guide to setting ignition timing:
http://www.tercel4wd.com/forums/viewtop ... f=7&t=5216
You should probably confirm the timing with a timing light.

It sounds like you are adjusting the choke in the right place. Inside the plastic cover is a temperature sensitive bi-metallic spring (like in a house thermostat) that rotates a shaft that has the choke plate on it. You should see the choke plate cover the mouth of the carb as you rotate the cover one direction or the other. This is usually how it works (but I don't have Weber so don't know for sure): With the engine cold, rotate the cover until the choke plate closes (you may have to hold open the throttle a little to get it to close completely), then tighten down the cover. Then drive it around until warm. The choke plate should have opened up all the way. If it is not open all the way, readjust hot to the point where it is open all the way. (and then check again cold).

Your hot running problems may be because the choke was not opening all the way.

Hope this helps.
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Re: weber carb help?

Post by Mogordo »

Hi all, This thread looks pretty on topic for the ideas I'm looking for so reviving it.
I'm getting to figuring out carb. and timing stuff to maybe get the car running better. It has a Weber though I don't actually know which model but I'd sure guess electric choke as there is a wire to the choke. It was installed, new I think, within the year prior to my purchasing the car last summer. The vacuuum was not hooked up in a way anyone on here reccommends. I went through and re-routed vacuum lines so I had carb. vacuum advance to lower port on dist. vacuum advance, manifold vacuum to upper port on same, PCV to homemade port where EGR used to be mounted. I checked ignition timing and changed it and will maybe get back to that because it still probably isn't ideal. And just yesterday capped off manifold vacuum port and upper port on dist. vacuum advance unit (before checking timing) because it appeared unplugging that line with car running did absolutely nothing and that I could suck air through it. But I wanted to adjust the carb. According to what I read on Redline website the base setting for idle mixture screw is 2 turns out and I got the impression that if everything else is set right the car should run well set within a turn or so of that. Do you think I understand that correctly? The mixture screw on the carburetor on my car was set at 10 turns out, it still runs fine at 9 turns but when I messed around with it a month or so ago any further in and car stalled. I don't remember though if I had the car warmed up. I thought I would start over and follow the guidelines on the Redline website but I didn't understand some of this: "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.)"
Can I just have the car fully warmed up and skip those steps? My understanding of carburetors is limited and I don't know to what a lot of that is referring.
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dlb
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Re: weber carb help?

Post by dlb »

Wow, this is an old thread. Funny to be reminded of when I was first learning about this stuff myself.

The first half of your post all sounds good, and yup your understanding of the Redline recommendation for Weber idle mixture is correct, and that's absolutely nuts if the idle mixture screw is out 10 turns. I'm surprised it even goes that far without falling out. I'm not 100% positive but I'm pretty confident that yes, as long as the engine is fully warmed up you don't need to block the choke valve open. All you need to do is take the air filter lid off and look to confirm that the choke (that's the top-most valve you see) is turned so it is straight up and down. If you know the engine is fully warm but the choke is still not vertical, you need to loosen the three screws and turn the plastic choke housing so that the choke valve is just vertical. Then you can go on with setting the idle mixture screw. I hope that makes sense, good luck!
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Re: weber carb help?

Post by Mogordo »

Thanks dlb! I thought it was a little funny when I looked at who posted the original message on here. A little different than your current postings (:
That definitely makes some sense. If it's not real cold outside tomorrow I'll probably have a go at it and see how I do. I too thought 10 turns was an awful lot once I read how close to the baseline it is ideally set. It's possible I didn't count right but I guess I can double check when I get back to it.
Thanks again, Cari
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Mogordo
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Re: weber carb help?

Post by Mogordo »

Got to it. I wondered if maybe before I counted a half turn as a full turn with the mixture screw, it was late, I had just finished working on something else on the car, my brain was addled...I did count wrong. It was turned out about five turns before, not ten. Still pretty far. I kept reading and called my dad to confirm a couple things and then I understood better what the Redline instructions meant. I also did another check for the ports on the vacuum advance unit. The one where you watch to see if the arm moves when you suck air through. The bottom one, which I still had hooked up, did move it. The top did not. I then followed the Redline instructions and the mixture screw is now around 21/2 turns out (I didn't do a final check) and the idle speed around 11/2 so good enough. The throttle was not releasing all the way sometimes though. Which I was wondering about because the idle is not consistent. I've come across ideas on here for fixing that so I can see if I can figure it out when I get there. The timing is set to around 10* BTDC, I have a little trouble telling exactly, which is a lot better than the around 4* it was at before. I'm interested to see if this all improves the fuel mileage, I'm thinking it likely, it was getting typically around 25 MPG before which isn't great. Especially since often something like 70% of my driving is on highways.
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dlb
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Re: weber carb help?

Post by dlb »

Mogordo wrote: Sun Feb 05, 2023 1:52 pm I'm interested to see if this all improves the fuel mileage, I'm thinking it likely, it was getting typically around 25 MPG before which isn't great. Especially since often something like 70% of my driving is on highways.
25 mpg does seem a little low for an '83 (which should have the 3.73 gearing unless it was swapped for 4.11's) but keep in mind that not all highway driving means better fuel economy. I find the higher above 100 km/h (or 60 mph) I go, the more fuel economy deteriorates. This has been consistent across all my vehicles that I've tracked mileage on.
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Re: weber carb help?

Post by Mogordo »

I don't much understand the gearing yet but I am assuming it is stock. Quite true, you can get poor fuel economy on a highway. I'd say for much of that highway driving our speed is 55-65mph. I plan to fill up the tank today and it will be close to empty in a few days so I'll get an idea soon. I've even been using the tactic of filling at the same pump each time after getting inconsistent numbers when I didn't.
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Re: weber carb help?

Post by Mogordo »

I checked four tankfuls of gas and had 28, 28, 27, 27 MPG so I think the tune-up helped. I am still figuring other things though. The timing is not too advanced unless I am confused but the engine sometimes pings severely and other times I can barely hear it. And not just because I have music on too loud (: Even though that does sometimes have me thinking the car sounds better than it does, I wasn't sure at first if not having music on was why I could hear the pinging but then could barely hear it another day even without music. Anyway, that's the thing I'm looking more into now.
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