1956 Thunderbird has trouble with cold start

zuburg

zuburg

Senior Member
I am having little success with a cold start on my 1956 Thunderbird (Teapot carb). Once I get it to start and help it to continue to run (keep my foot on accelerator so it won’t die) until it warms up it, runs great.

I have an electric choke. It appears to be working as the butterflies are closed when cold and begin to open as it warms up until they are fully open and running smoothly.

Usually when I try a cold start (after pressing the accelerator to the floor once and take my foot off), it quickly fires and just as quickly does. Once it dies, it doesn’t fire again without cranking it for a very long time and then it struggles, trying to fire several times until it finally fires and starts. It runs rough then and won’t idle at normal RPMs and dies. I have to keep my foot on accelerator to keep the RPMs up and usually keep the RPMs at 1750-2000 as it runs smoother there. I can reduce the RPMs in steps until it will hold idle at a normal 675-700.

I tried adjusting the screw on the fast-idle cam by turning it clockwise (without any change). I also adjusted the electric choke to make it more lean.

What other steps should I try?
 
Not that I have a clue what might be wrong but just to provide info to others...
How long does it sit between cold starts? A couple days? A couple weeks?
Have you checked the fuel pressure?
Is there any soot in the exhaust outlets? What color?
 
It happens the next morning after I drove it over 20 miles. Or even just later in the evening after a morning start.

I do have black liquid coming out the exhaust pipes that I assume is soot mixed with condensation?

PS. This black liquid has been coming out for years, even before I had problems with the cold start.
 
Last edited:
Here's why I asked the questions I did...
A couple years ago the fuel pump in my '55 was failing and couldn't keep up at all. Hard to start and didn't want to run

If the exhaust smell is pretty strong something may be causing the carb to run too rich.
Hopefully the following is relevant???
Just 6 or 8 weeks ago mine began spitting out more wet black soot than usual when starting and would quit right away. Acted like it was flooding and fouling the plugs.
But I didn't pull them to check because... once I was able to get it started and running the exhaust was literally trying to to gas me out of the car. So I knew the carb (not a Holley 'teapot') had a serious problem. A carb swap confirmed it.
 
I don't know anything about a Teapot Carburetor, but could the carburetor be draining down over night and is just priming the cylinders on your first start. On this carburetor can you check you to see if the float bowl has gas in it before you start it and I would check the oil to see if it has a gas smell.
 
It happens the next morning after I drove it over 20 miles. Or even just later in the evening after a morning start.
Click to expand...

If it happens most every start attempt, before start remove the ACL and open the throttle linkage to see if a shot of fuel enters the throttle body (accelerate pump). If not, open the throttle linkage again and with a flash-lite see if fuel is puddled on the intake manifold floor.

If the choke and linkages is adjusted correctly, you should be able to floor the accelerator pedal once, remove your foot and crank. If a good tune, she should fire.

This is a stock 1956 FYB with an H4000 and L-O-M?

If the muffler is full of carbon so are the combustion chambers and plugs.
 
You must log in or register to reply here.
Back
Top