Automatic Choke Functions

6

60s Refugee

Well-known member
Hi All!
On a '65 Autolite 1100, just what all does the automatic choke do? Here's why I ask: I installed a rebuilt 1100 on my 200 when I restored it. Pony did the rebuild. It would run, but nothing to get excited about. Performance was just average with the common flatspots, hesitation, and other 1100 issues. I also had ping at higher speeds that I finally just gave up on. The coming of cold weather made the engine hard to start. Finally I removed the choke spring cover to see what was wrong. I found the choke spring had fallen out of the slot that holds it. The spring loop was not over the butterfly arm either. I don't know if it just fell out or was never in the right place from the start. I put the spring back in the slot, put the loop over the butterfly arm and reinstalled the cover, being careful to set the choke properly.

I expected the engine to start easier, and it did, but, the engine just plain runs better! Hesitation is gone, no flat spots, and no ping at 75 MPH! It's like a whole new carb. Pony said their rebuilds improved the original design, but I hadn't seen it until now. So what else is happening besides the butterfly closing and opening properly?

Thanks,
Harry
 
If the little tang on the spring was on the wrong side of the choke lever the airflow through the carb could have been sucking the choke shut.
 
On my Pony carb, those a$$holes put the choke coil spings on backwards. So as the choke got warm, the coil CLOSED the flapper. Pony=POS....
 
mugsy":7dveiabn said:
On my Pony carb, those a$$holes put the choke coil spings on backwards. So as the choke got warm, the coil CLOSED the flapper. Pony=POS....
Click to expand...

For what you pay for those things you would expect more. If they screw up easy stuff like that you wonder how they do on the hard stuff. You hope it was just a new guy that had just put together a bunch that were supposed to be that way and didnt notice he was working on a different model.
 
Here's the latest. I went out this afternoon to check the carb again. ook the air cleaner and started the engine. Started fine. Ran it down the road and warmed it up. Choke butterfly was only open about 2/3 of the way. I reset the choke to full open. Took it out again and CRAP! the hesitation on accelleration was back! Guess it was running better because it was running too rich.

Harry
 
With the info provided last, the situation starts to make since.

The engine or carb is running lean and needs re-jetting. The partially closed choke plate would provide a richer not too rich condition in the main circuit. I say it that way because in your first description you described the pinging at cruse which is the main circuit. If you are lean and running hot, the elevated heat is another way to cause pre-detonation.

Then again the jetting could be correct and you could have a vacuum leak. The leak would cause the same symptoms.

Use some carb cleaner or another type of spray at the base to check for the leak.

Good luck, Ric.
 
You would think.

Thats why I mentioned the vacuum leak. Pony carbs are considered a quality carb so douple check for the vacuum leak. Plus that is the easiest between the two to check.

Good luck, Ric.
 
Ric,

I hadn't thought about a vacuum leak. Went out today and started looking. I didn't expect to find any gasket issues, and I didn't. What I did find was a stupid oversight. The rubber hose from the PCV to the carb base was split! I had used the 43 year old hose over. It had split at the carb base nipple. I replaced it with a new hose and two new clamps.

On the way home I put 'er to the test. The hesitation is gone, but I still have minor ping at hard accelleration above 65 MPH. 92 octane gas.

I have not touched any carb or distributor settings as yet.

Harry
 
Back your distributor off just a touch. The ping on hard acceleration should disappear.

Hesitation is a different story. Either too much fuel all at once or not enough (dashpot or accelerator pump) if your ignition is giving a hot spark.
 
Watch the engine temp as well. Make sure the temp gauge is correct and that you have the correct heat range of plug. The extra heat with the low octane fuel of today and the original high compression will give you ping.

Good luck and have fun, Ric.
 
Temp seems OK and has been right along, even in hot summer with AC on. I'm using OEM Autolite plugs with a Pertronics II ignition and the hotter coil. I set the plug gap at 45.

Harry
 
Per Falcon Six Performance Handbook, with that setup you can use one grade colder plug and open the gap to 55.
 
Ask your parts store. Use the the number you have as a starter. David Schjeldal actually knows the numbers. Do a search on his posts.
 
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