2150 carb question

[gws34]

I have a "new" 2150 carb from autozone that I have installed on my 75 bronco with a 302. As I am trying to tune it I am ending up with my mixing screws out to almost 4 turns starting at 1 1/2 turns, this is where it gets to optimum vacuum pressure and holding steady at 18.

Does this seem like it is out to far? what could be causing it to have to be that much out (if it is an issue)? Hoping to get it on the road and pass emissions once this Covid thing has passed.

When I run it leaner than that, i get the surging of the engine
( by almost 200 rpms- i.e 700 to 900rpms not holding steady

Been trying to get this bronco on the road and replacing all of the emissions stuff the PO took off.

Thanks for any help.

 

[ared77]

Seems too far out to me, like maybe there is still a vacuum leak? I'm just a shade tree mechanic so hopefully others will chime in.

 

[jckkys]

Do you mean by "new", a Chinese knock off or a NOS Motorcraft 2150?

 

[WheelHorse]

My idle screws are out three turns...genuine motorcraft 2150.

What year is your Bronco? If you have a brake booster, make sure it is not leaking.

Unlike a Holley, there's no air bleeds to change, so maybe one of the 60 year old Bronco guys could chime in with some experience.

I was IL IM240 certified for emissions, I can tell you I had better luck tuning the idle with a vacuum gauge than an AFR meter and getting carb'd vehicles to pass.

If you only have to pass and idle and visual, that's easy. The dyno was not as easy to fool.

 

[gws34]

I believe it is not genuine motorcraft, have to go out and look at it. I am using a vacuum guage, I was getting steady pressure when they were out about 4 turns. It seemed like a lot to me so I started over at 1 1/2 turns and turned up to 2 1/2 turns but still get surges while it is running.

I have never gotten and older vehicle inspected here. our newer vehicles they just plug in. I have had this bronco for many years, took it of the road when I moved to AZ and am now trying to get the emissions up to par and get this back on the road. Here you have to get the emissions testing done before you register it. So i am trying to get it as ready to go before I take it over. I have to insure it to drive it over for the testing and get a temporary registration that is only good for 3 days. I would rather not just guess that it is going to pass and then have to do this all over again.

I do believe it does have to go on a dyno for this year.

Thanks

 

[gws34]

No brake booster, again been replacing most of the vacuum lines and emissions stuff and replacing it.

Thanks

 

[gws34]

Update:

it is a national 2150 carb-not motorcraft
With three turns out each mix screw I get a steady 20 in hg of vacuum.
With the vacuum advance hose off and plugged -at 600 rpm I am set at 6 degrees BTD, and when I connect the vacuum advance it idles at about 800 rpm.

Does this all sound like it may be close enough to stock to help it pass emissions?

I fell better that wheelhorse said his are at 3 turns for a true motorcraft.

thanks for the help!

 

[ared77]

"a steady 20 in hg of vacuum" sounds good to me, I'm guessing you'll be alright.

 

[jckkys]

I guess what you mean by a new 2150, is that it's new to you. National is one of the large scale re-builders that toss the ID tag so you don't know what carb you have. Do you know what size venturis the 2150 has? There is also ID info on the vertical surface of the front left hold down "foot". Can you share that? National rebuilds carburetors they don't manufacture them. Real 2150s are made by Motorcraft whether for Fords or AMCs. The word Motorcraft is cast on the top of the top cover. That is, unless it's Chinese.

 

[gws34]

I did not see motorcraft on it but I will look again tomorrow. I will lokk for the number on the foot also.

thanks

 

[gws34]

Yes new to me.

 

[WheelHorse]

The biggest helper will be a new catalytic converter. A new cat will clean up a lot. Trick is run it during inspection time and save it for your inspections.

 

[jckkys]

The emissions test in Tucson, actually Pima Co., is little more than the sniffer in the tail pipe to check for CO and hydrocarbons. The carburetor can be adjusted to pass that. The inspection looks for things that may have been removed. I had removed the air pump and the EGR, but made it look like they were never there so they passed me. They do look for a PCV, but you want that anyway. Don't over think this, the inspectors sure don't.

 

[nvrstuk]

Guess I can never move as I don't have any stock parts on my Bronco anymore... do they test ALL vehicles in AZ or just certain years...