1957 312 hesitation/stuttering under acceleration

[CHAMBERS777]

Hi there,

Looking for help and advice on this, under acceleration the car seems to stutter and splutter for a second or two and then finally finds itself and kicks on. It is definitely more pronounced when going uphill, I’m not talking of heavy acceleration or anything just general driving around town and the suburbs etc. I’m also getting quite large drafts of burnt gas/exhaust smell when I have the windows down and driving which I haven’t noticed before, I’m wondering if these two issues could be connected. It’s a rebuilt motor with around 2500 miles on it, The car starts hot and cold with no issues, one turn of the key and she goes, I’m running a electronic ignition and Holley 600CFM carb. In drive she idles around the 500rpm mark, in neutral between the 700-800rpm range. I have noticed that on start up and backing out the garage she spits out some black soot on the ground, I thought that was pretty normal as I think on cold idle these things run pretty rich.

Because of the lockdown over in Scotland I haven’t managed to drive her properly for best part of a year, she has been started every month, brought up to operating temp and shut off. Last summer the spark plugs were changed out to some good premium ones sold from one of the T Bird suppliers, that’s all that I have changed ignition wise, never had any issues with accelerating or excess exhaust fumes in the past.

Any ideas where I could start with this, running too rich?? Needle/float issue?? other than this the car does run very very well

Appreciate any advice or help, many thanks for your time.

Chris Chambers
Prestwick, Scotland

 

[OhioTbird]

Had a similar issue with a VW Bug.
1) replace the fuel filter
2) clean or replace spark plugs

 

[Frankie the Fink]

A general tune-up may help, I don't know what "electronic ignition" you have but sticky centrifugal advance weights in the distributor, deteriorated carburetor accelerator pump, timing, weak fuel pump and a host of other issues could be the cause. Read down this page about "Bog, Hesitation, Stumble" for more info:

 

[Douglemmo]

I would check to see that your choke is adjusted and functioning properly . You could also check the float level, which is quite easy to do on the Holly. As I remember there is a sight plug on the side of the fuel bowl. With the plug removed, the correct level should be right at the bottom of the plug.

Good luck