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Carburetor
#1
Hello,

      Anyone have a simple step by step guide for adjusting the Autolite/Motorcraft(?) 2100 D 2 barrel carb in my 73.  I believe it is running rich based on smell.  I have a timing light, tach and vacumn guage.  I was able to get it adusted several years ago and it seemed to run fine until recently. I know all the basics as far as idle speed, mixture screw ... just want to make sure it is not running rich.  Also has the original electric choke.  Thanks very much for any guidance.

Steve
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#2
So, I can't give you what you want, but I can give you something.  Rich at idle can be adjusted with the idle air screws.  Rich anywhere else generally is a result of improper jetting.  Since jetting only changes when you actually choose to replace the jets, you have to look elsewhere when the problem develops.

Idle changes do require readjusting the idle air screws afterwards.  https://itstillruns.com/adjust-twobarrel...16889.html gives you basic adjustment procedure

I would suspect that if the rich situation is new, then your carb may have trash in it plugging an air bleed, or the choke adjustment may be keeping the choke partially engaged.  Perhaps gaskets are not sealing.

anyway, here is a stolen post that describes choke adjustment

That 2100 auto choke is actually not that bad to adjust, but there are a couple of tricky things involved and you have to do them in the right order.

In order to explain things so we first have to ASSUME a few things. I am assuming that you firstly have the correct carb installed on you stang. Next that carb is in good general shape and not needing a rebuilt. Then everything with the choke is assembled correctly, not broken and operating as intended. And finally the choke tubes (notice I said plural as there should be two a hard line and a vacuum type line (intake and outake)) are installed and not blocked and operating.

So now that I eliminated 80-90% of you (yes the number is that high of the above problems on working cars)

The first adjustment is to adjust the vacuum piston choke pulldown adjustment which is the trickiest thing and what most people miss. Take a paper clip and straighten it out and then bend the tip 1/8 of an inch from the end into a 90 degree bend. take the cover off of your choke and ru nthe clip down the tube between the slots on the brass head of the piston on the forward side. As you slid it against the wall you will "feel" a ridge. Put the end up against the ridge and pulle the piston up till it stops against this paper clip. Now measure the distance between the choke flap and the front wall (for your mustang a 1/8 drill bit should just fit with a bit of resistance) You can get this adjustment by turning the plastic nut on the choke flap.

Next is the fast idle cam linkage. Install the cover and turn so 90 degrees past index. Then place fast idle screw on the mark of the fast idle cam(should be an x or v). Then again measur the choke flap to the front (again this time a 1/8 inch drill bit should fit with a bit of resitance) this time you get the adjustment from the "small bolt" behing the choke that the choke flap rod attaches to.

The last thing to do is to set the fast idle adjustment, again place the fast idle screw on the fast idle step (the X or V again) then adjust the idle to 1600 using the fast idle screw.

Install the choke cap which should be set at 2 mark to the rich side of the index for an Automatic trans.

Again these setting are ONLY for a 1966 automatic transmission mustang and 1966 mustang carburetor.

Good luck,

Hope that helps, any other questions shoot them here or E-mail me directly

Bill White
White Automotive

This will give you something to do at least Big Grin

[Image: 1_01_07_15_8_53_18.png]

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!
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#3
I had a similar experience, except the gas smell was due to a fuel pump cracked diaphragm that allowed gas to leak out of the weep hole on the original Carter pump. I had just had the 2100 rebuilt and knew it was tight. Just check (eliminate) the obvious things before blaming the carb.

Sent from my SM-G900P using Tapatalk
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#4
Good point and as I often say 90% of carb problems are electrical, so check your plugs, wires cap rotor and coil while you are chasing a problem.

[Image: 1_01_07_15_8_53_18.png]

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!
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#5
if motor has not been rebuilt, still has original harmonic balancer, outer ring probably has moved. set timing by ear, get it to where it starts easy and shuts off easy. put vacuum gauge on it, adjust carb to get highest vacuum, set idle, drive car and see if you getting any pinging. do the easy stuff first and write it do down so you don't forget
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#6
(09-30-2019, 05:17 PM)164runner Wrote: if motor has not been rebuilt, still has original harmonic balancer, outer ring probably has moved. set timing by ear, get it to where it starts easy and shuts off easy. put vacuum gauge on it, adjust carb to get highest vacuum, set idle, drive car and see if you getting any pinging. do the easy stuff first and write it do down so you don't forget
Hello,

      Have checked many of the above items.  Car runs well and performs well.  No running on when shut off and no pinging. Choke operates properly and opens all the way when warmed up.  Did have the carb professionally rebuilt a few years ago to stock set up.  My reason for this post is that when I drive it and shut it off there is an odor of gas not overwhelming but more than I think should be present same when idling. Also, I change the oil every Fall .... if I smell the dipstick there is a faint odor of gas.  Am running a Pertronix system in distributor with a hotter coil.  The sparkplugs are original to the car when I purchased five years ago.  I have never changed them and they have app. 3K miles on them.  Should they be replaced and any recomendations ?  Plug wires have been replaced in last couple of years.  Otherwise the engine runs well and performs well.  Thankš
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#7
What do the spark plugs look like, fouled/black or brown/tan?

Have you tried smelling the oil after you shut it down and smell gas? The fuel pump can leak directly into the crankcase.

Is your PCV valve and hoses all connected and operational.



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
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#8
(05-04-2020, 09:24 AM)Don C Wrote: What do the spark plugs look like, fouled/black or brown/tan?

Have you tried smelling the oil after you shut it down and smell gas? The fuel pump can leak directly into the crankcase.

Is your PCV valve and hoses all connected and operational.
Hello,

    Will have to pull a few spark plugs and see what they look like .... should I pull them all initially or maybe one from each side ?  If I go out at anytime and smell the oil I smell a light odor of fuel in it.  All the vacumn lines and PCV valve are correctly attached and operational.  Thanks
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#9
Fouled plugs will allow unburned fuel to coat the cylinder walls and wind up in the crankcase.

I would pull all of the plugs, just one bad spark plug will cause all sorts of problems. They might fire when idling, but under the higher pressures generated during running not be able to fire.



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
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#10
Ok ....will do .... I'll post what I find. If they are burning correctly they shoudl be brown/tan ? If that is what I see I guess I can reinstall them. If the carb is running rich or have a bad plug would I see black carbon appearance ? What would you recommend for a gap on my plugs ? Stock motor with dual exhaust. Thanks
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