This is a bit newbie but....

The below three pics are of a reman'd carb I bought some time ago to pass smog which has run great and I've had no complaints about. In fact it ran so well, I stopped fusing with the Holley 4 bbl that I never could get to run. Anyway, I don't know jack about carbs...specifically what adjustments that can be made to this one. Frankly, beyond idle adjustments I simply don't have a clue. There are no numbers stamped on it that I can find to identify it. I was hoping someone would recognize it and tell me what to do to check/adjust for a tune up. I know there are two screws on the front side bottom plate...one on each side...that the smog shop adjusted to get the mixture right which I did pass. But, that was about 6-7 years ago. I haven't touched it since. Any help would be appreciated. :D

Oh...Yes I know...get EFI. I would if I had the money.

http://home.comcast.net/~mallen51/xmas03_072.jpg
http://home.comcast.net/~mallen51/xmas03_073.jpg
http://home.comcast.net/~mallen51/xmas03_074.jpg

Is this an early Bronco? I had a similar 2V on mine, I believe it was an Autolite/Motocraft 2150 or 2100. I'd start by searching for pics of those. I did a quick Google search, looks like there's a decent bit of chatter out there on IDing these, due to the Mustang/performance crowd.

Other than fuel slosh caused by hard hits, my 2V worked awesome offroad on angles and inclines, much better than any 4V I've ran. I was going to swap a cheap Q-jet on mine but found a great deal on a 5.0 setup.

yup looks likea 2150 to me

I think it is a 2100 2150 too....Adjustments?

The extent of my knowledge:

The two screws up front are mixture screws. The rebuild kit instructions say to 1) turn the screws in until lightly seated, then 2) back them out about 2 turns, 3) adjust them until best/smoothest idle is achieved. Of course sometimes you may have to adjust the idle speed (throttle stop) to get the idle fast enough to smooth out the mixture.

I am by no means a carb expert but I kept mine tuned like this while I had it.

More info...it is a 2100 autolite from 1970-71.

Do I turn each screw the same...one for each barrel? Can anyone confirm the number of turns?

Anyone need one...there's one on EBay for cheap...Just FYI:

CARB (http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33550&item=2455074303)

I think you need to turn them the same amount. I would just turn them both about a 1/4 out at a time until I got close. I don't remember how many turns--it will vary anyway. You'll know when its right. If its running decently now, count the number of turns in until seated, and use that as your base when you back them out.

It runs fine, passes smog, run's off-camber, you have no problem with it. Why the hell do you want to dick with the adjustment screws? Go find something that's broke and fix it. :flipoff2:

Might want to ask some jeep guys, they seem to like to swap this carb onto their junk. To the best of my knowledge, there really arent any mods you can do to it, but it runs great anyway. The bronco repair books (chiltons, haynes) tell about adjusting the carb...

It runs fine, passes smog, run's off-camber...

Trust me...I live by the..."If it ain't broke don't fix it" rule.

I believe the mixture is off and it is not running great right now...especially in the mountains which is normal to some degree, but not this bad. It is my understanding that you should lean out a bit at 6,000+ feet since the air is a bit thinner. If that is true, and I am only 80% sure it is, then I suspect I am running a bit too rich overall. I don't even know which way to turn to add or decrease fuel. Hence the post.

:flipoff2: ;) :D

I have the fatty Chiltons book specific for the EB which list all the carbs etc, but the damn thing doesn't say diddly about mixture adjustments...

The screws are only for the idle mixture. If you wanted to lean out, you would have to change the jets in the bottom of the float bowl to a smaller size.

Also if you look up, you'll see the topic "TOTM: Ford carburetion"...... don't even have to search ;) Alpo offers some great info these carbs.

When I adjust my 2100 and my q jet I hook up a vacum guage off the manifold and turn the idle mixture screws the same amount until I get the highest vacum readings.

Originally posted by Howdy
When I adjust my 2100 and my q jet I hook up a vacum guage off the manifold and turn the idle mixture screws the same amount until I get the highest vacum readings.

I haven't done it this way but a lot of guys have and swear by it.

the other meathod of tuning that I know of is using the tach. you adjust the idle screws 1/8 or less at a time. go for 'max lean' this is when the idle speed is highest. proccedure is adjust screw, wait 20 seconds or so and see what the idle speed does, you want to keep adjusting in a direction that increases speed until it starts to decreas again. you are not going for the fattest idle mix but the leanest that will run smoothly, too lean and the idle speed drops off just as if you had it too fat.

The vacume gauge method is doing the same but is a quicker,but arquably less accurate, means to the same thing.


I've done both and I personally tend for the Tach method.



As for the Carb pictured. look on the side of the base plate under the accelerater pump rod for a stamped number, as well as a cast number on the side of the bowl by the accelerater rod.


Eric

The screws are only for the idle mixture. If you wanted to lean out, you would have to change the jets in the bottom of the float bowl to a smaller size.

Thanks!

And Alpo...thanks for the details:D Sounds like that is all there is to adjust on this carb. Yes?

Can running lean create a hot engine? Mine is hot enough now.

Originally posted by NOTPRETTY

Sounds like that is all there is to adjust on this carb. Yes?

Can running lean create a hot engine? Mine is hot enough now.


Too lean on the main jets will run hot and can start pinging too.
Also cam timming plays into it as well as ignition timming, but that is another area.

the only other adjustments are float level and accelerater pump rod placement. the later changes the amount and duration of accelerater pump.

Eric

Since we're on the topic, I'll add these pics.

One of the reasons the Motorcraft carbs are good offroad performers is the location of the primary jets. Note that they are Centered on the Bottom of the float bowl. This is the best location for the jets, as they will remained covered with fuel even at pretty severe angles.

In yellow, I've marked where the jets are on my 2bbl holley that I'm currently running. They are on the back of the bowl and spaced out to the sides. So on steep nose down angles, the jets starve for fuel, and in off camber situations, one side may starve. Amazingling, my holley performs extremely well offroad. All I did was lower the float level as low as I could. I've had my bronco on the verge of rolling many times, and it just idles away.

I've always been disappointed with the choke operation on the Motorcraft carbs. Other than that, they work very well.

The next photo shows the venturi size stamp that Alpo refered to. Very handy to know!

http://www.broncoii4x4.com/bb/motorcraft-jets.jpg

http://www.broncoii4x4.com/bb/motorcraft-stamp.jpg

I love my 2 bbl. on my Early Bronco , an old blowed up 302
that ticks like a sewing machine , but runs hella fine . Sidehills,
off camber , up steep hills , no probs . Only one episode of bad
running , smashed a big rock with the stock gas tank and broke
loose some funk . Got in the jets , fine after rebuild . :flipoff2: