Topic: 66 6 cylinder Mustang hesitation when pressing gas

[KenStang]

Hello to all,

I have a 66 Mustang with a automatic 200 cubic inch 6 cylinder.  It had been sitting for a while and wanted to get the car driving and running better.

I pulled the Autolite 1100 carburetor and rebuilt and found many issues.  I think I now have them all corrected and reinstalled the carb recently.  The care is now idling very well, and running very well.  It is not missing and seems to drive good.  The only issue that I have been able to resolve is a hesitation that I get when you first punch the gas at a dead start.  If you continue to press the gas it will stall and if you back off and then re-push it will go fine.  Once driving the car runs fine.

It seems like this is a accelerator pump issue but I have it adjusted per the manual specifications.  It is in the HI position and set to 3/16" gap with the throttle plate closed.

I know that you have adjust the linkage by bending if this gap is wrong but my gap is not wrong. (I believe).  Also the float was adjusted in the carburetor to 1 1/32" distance based upon manual.

I know that I will get in trouble with the purists but I did replace the points and condenser with a Petronix ignition and this did not seem to help the problem.  It also did not seem to hurt the problem either.

Any help would be apprecited.

Thanks

[67gtasanjose]

You seem to be on the right track with accelerator pump adjustments. You describe a "Lean Stumble" which if enough gasoline injected into the Venturi, it would go away. If you can find a local shop with a Dyno, I am sure they can assist with dialing in the right curve easier than a hunt-n-peck, do-it-yourself kind of a job. Just a suggestion, or also, work on hunting/fixing any sources of a vacuum leak (including but not limited to an incorrect PCV valve).

[KenStang]

Curious - How does the PCV associate with this problem?  I have searched for intake leaks using carb cleaner but not found so far.

Thanks
Ken

[67gtasanjose]

The PCV Valve is essentially an orface that is calibrated to match jets, venturies and assists other proper functions of the carburetor...call it an "engineered-in vacuum leak" so to speak. Though we look at it as an item designed to prevent crankcase pressure (replaces the road pipe principle) while also drawing in un-burned gasses that get past the piston rings (helps the environment ~pollution control), an incorrect valve with an "orface" that is too large, you will have a hidden vacuum leak (so to speak).

[NEFaurora]

"Also the float was adjusted in the carburetor to 1 1/32" distance based upon manual."


That distance is wrong.

It should be a distance of 1 3/32" or 1.090 in decimal.

Also, The Jetting for an I6 C4 Transmission should be "67" or "67F".... Check the Jetting on the carb as well.


)

Tony K.