My dad and I have been trying to fine tune the air/fuel mixture screws on the Autolite 2100 carburetor and we can't seem to get it just right.

Symptoms: In the morning when we start it, it starts fine and choke works great (fast idle), after about 5-10 mins, we tap the gas once to get the idle to drop to regular rpms. Shift to drive, apply gas and it BOGS then goes. Sort of like it's going to die then comes to life and moves. Never actually dies, just BOGS down.

Adjustments we've tried when the engine is warm:

1. Screw both screws in all the way, then turn both of them out 1.5 turns. Doesn't start. Then we tried a total of 2 turns out and it starts fine. A little rough so I turn it out another 1/4 - 1/2 turn on both ends. It idles and runs great when warm but BOGS when cold.

2. Did the above but with 2.5 turns out. Still the same.

I know this isn't normal, because my '66 fastback 289 2bbl doesn't bog at all at any temperature.

Please help. The only screws we've messed with are the air/fuel mixture and idle. I'm not sure what else there is to adjust on this carb.

Thanks in advance.

Erik

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1966 Ford Mustang 2+2
Mine - Restomod in Progress

You need to check your choke thermostat coil, and choke linkage. What it should do is the choke plate should snap shut firmly when the engine is cold and you depress the throttle to the floor. That also sets your fast idle cam so the engine idles a little quicker while it warms up. As the engine runs, the choke thermostat should open the choke fairly quick, with 3-4 minutes or so, then the choke plate should be straight up.

To set up the choke, start with the marks straight up, and if the choke plate snaps shut firmly, you're there. If it's weak, you can move to 1 rich, 2 rich, 3 rich, etc, but remember the richer you set it, the longer the choke will work, wasting gas.

After you get the choke plate where you want it, check the operation of the fast idle. I never used to set them at factory spec, because I always liked my fast set at 1000 or so, just fast enought to keep it running smooth but not overrev it while it's cold. That is set with a screw on the fast idle cam behind the choke thermostat. You can set this with the engine warm by just moving the fast idle cam into position with your finger.

I think I may have mis-worded my 1st post.

The problem is really when I start to drive the car when it's just been warmed up. I never really thought about the choke plate being a problem. I'll have to take a look at the choke plate after I tap the gas to get it to idle low.

Bluestreek,

The previous owner claimed he had it rebuilt about 20k miles ago so I assume the carb is still good. It runs great when warm/hot. Just that first 5 mins after it's been started is when it bogs from a stop to acceleration.

Let me know if I have confused any of you.

Thanks in advance.

Erik

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1966 Ford Mustang 2+2
Mine - Restomod in Progress