1956 Problem starting when cold

[rdeleo]

1956 TBird. When cold my car takes a number of hits on the starter to get rumbling. After start and warming up she runs fine and starts fine. I am sure without fuel injection this is nothing new but this car takes a long time. Has anyone added a choke or is there something else to consider?

This page contains affiliate links for which I may be compensated. As an eBay Partner, and Amazon Associate I may be compensated if you make a purchase at no cost to you.

 

[BGordon255]

There should be a choke on the carb. It may be mis-adjuster.

 

[Shawnski]

1956 TBird. When cold my car takes a number of hits on the starter to get rumbling. After start and warming up she runs fine and starts fine. I am sure without fuel injection this is nothing new but this car takes a long time. Has anyone added a choke or is there something else to consider?

My ‘56 baby bird typically does the same after sitting for 3 or more days. I do have the original Tea Pot 4 barrel with the automatic chock that is set up and works perfectly. I had seen many other having similar issues and they found that the fuel would siphon back and or just evaporate. Some installed an anti siphon valve in the fuel line between the carburetor and the fuel pump. I tried this and had issues with the engine starving for fuel at times while driving. So, I opted for an inline electric fuel pump that I only use if she doesn’t start after the first crank of the starter. I just manually turn on the electric pump for about a count of 10 to 12 seconds, turn the pump off and crank it again where she starts pretty quickly.
I bought the pump sold in the CASCO site that’s designed for our baby birds. It mounts inside the frame rail where there’s a factory hole for those that had a standard shift model where I believe the clutch arm is mounted. Obviously if you have a standard shift model, you will need to mount elsewhere..

 

[Frankie the Fink]

You have a choke issue - seriously doubt its evaporation even so, a properly operating fuel pump fills the fuel bowls up in seconds. When I rebuild carbs (I've done dozens) and put them on a car bone dry, it takes just 5-7 seconds for the engine to light off, and usually on the lower end of that range. You have something mis-adjusted.

 

[doug7740]

1956 TBird. When cold my car takes a number of hits on the starter to get rumbling. After start and warming up she runs fine and starts fine. I am sure without fuel injection this is nothing new but this car takes a long time. Has anyone added a choke or is there something else to consider?

This is the starting procedure I use on my 6 volt,1955 Thunderbird.

Engine Starting Procedure​

Cold Engine - Sitting Overnight - Sitting For A Few Days

• Do not touch the accelerator; crank the engine over for 5 seconds.

(This not only fills the fuel filter bowl with fuel, it also builds up oil pressure)

• Slowly push the accelerator pedal to the floor and then slowly release the accelerator pedal.

(This closes the choke assembly and primes the carburetor with fuel)

• Do not touch the accelerator; crank the engine over for 5 seconds once again. If the engine starts, rev the engine once slightly.

If the engine did not start, depress the accelerator 3 times, but only ¼ pedal travel each time.

(This primes the carburetor with additional fuel, but keep in mind, T-Bird engines flood easily)

• Crank the engine over once again and when the engine starts, rev the engine once slightly.

Warm Engine - Sitting Less Than An Hour

• Do not touch the accelerator; crank the engine over and when the engine starts rev the engine once slightly.

Warm Engine - Sitting More Than An Hour

• Depress the accelerator pedal ¼ pedal travel and hold it in that position. Crank the engine over and when the engine starts rev the engine once slightly.

doug7740
1955 Thunderbird Blue

 

[Tom Alpers]

This is the starting procedure I use on my 6 volt,1955 Thunderbird.

Engine Starting Procedure​

Cold Engine - Sitting Overnight - Sitting For A Few Days

• Do not touch the accelerator; crank the engine over for 5 seconds.

(This not only fills the fuel filter bowl with fuel, it also builds up oil pressure)

• Slowly push the accelerator pedal to the floor and then slowly release the accelerator pedal.

(This closes the choke assembly and primes the carburetor with fuel)

• Do not touch the accelerator; crank the engine over for 5 seconds once again. If the engine starts, rev the engine once slightly.

If the engine did not start, depress the accelerator 3 times, but only ¼ pedal travel each time.

(This primes the carburetor with additional fuel, but keep in mind, T-Bird engines flood easily)

• Crank the engine over once again and when the engine starts, rev the engine once slightly.

Warm Engine - Sitting Less Than An Hour

• Do not touch the accelerator; crank the engine over and when the engine starts rev the engine once slightly.

Warm Engine - Sitting More Than An Hour

• Depress the accelerator pedal ¼ pedal travel and hold it in that position. Crank the engine over and when the engine starts rev the engine once slightly.

doug7740
1955 Thunderbird Blue

Doug, not to argue with what works for you but if you rev the engine as soon as it starts you will let the fast idle cam drop. I do pretty much what you do except for the revving the engine part when it starts. I let it run on fast idle for a minute and then blip the throttle to drop it down off the fast(est) idle cam.

 

[Birdman of coatesvile]

Had same problem on my 1955, rebuilt carburetor starts fine now.

 

[Old Marine]

There should be a choke on the carb. It may be mis-adjuster.

On some of the Ford carburetors they used a "power valve" sometimes located on the bottom side of the carburetor. When those go bad the engine starts real hard when it's cold. I don't know if that valve adds any power or not but I do know when they are replaced the engine starts much easier.

 

[rdeleo]

My understanding from comments is that the automatic choke is the round device on the side of the carb. I loosened the three screws and rotated the device both clockwise and counter. It changed the idle speed but the choke flaps did not move, they are stuck full open. So unless I am trying the wrong piece of equipment I am at a loss. Any help?

 

[doug7740]

If when you rotate the choke housing the choke plates do not move tells me that the choke control rod is not connected to the choke plate link.



On this carburetor, the richer mixture required for starting and operating a cold engine is supplied through the use of an automatic choke. The choke shaft in the carburetor is linked to the choke mechanism with a choke control rod. Two offset choke plates at the entrance of the air horn control the airflow into the primary barrels.

The bi-metallic thermostat spring in the choke control mechanism will expand when cold, loosening and unwinding its coils. When warm, it will contract, winding the coils tighter. When the engine is cold, the thermostat spring expands, holding the choke plates in the closed position. When the engine is started, the manifold vacuum acts directly on the choke plates, immediately moving them against the tension of the thermostat spring to a partially open position to prevent stalling.

As the engine continues to run, the vacuum acting on the choke vacuum piston draws filtered air from the carburetor through the heat tube in the intake manifold where the air is warmed by the engine heat, and then through the thermostat housing where the air warms the thermostat spring, causing it to contract. This gradually decreases the tension of the thermostat spring as the manifold temperature rises, permitting the vacuum acting on the choke vacuum piston to further open the choke plate. When the engine reaches its normal operating temperature, the thermostat spring no longer exerts an opposing tension on the choke vacuum piston, allowing the vacuum piston to pull the choke plates to the fully open position.

The automatic choke is accurately set at the factory to give the best possible all-weather operation. To return the choke to the original setting, line up the index mark on the rim of the thermostat cover with the large center indicator on the choke housing. If for some reason a richer or leaner mixture during the warm-up period is desired, it can be obtained by rotating the thermostat cover. Never set the index mark on the cover more than two graduations off the large center indicator on the housing.

doug7740
1955 Thunderbird Blue

 

[rdeleo]

Thank you. I am trying to follow your excellent diagram. The problem with the choke plates is that they are solidly in place. You cannot move them. So if the levers were not connected I would assume you could. Is it possible that something in the choke assembly is stuck thereby bot allowing any movement. I think my answer may be to send the carb off somewhere for rebuild. I am not a mechanic beyond tinkering which has not helped. Again thank you.

 

[Frankie the Fink]

You've found your issue and if the choke plate isn't moving that's a problem...

If you look at the above picture you will see in the round housing that there is a piston inside that housing called the PISTON AND LEVER ASSEMBLY. VERY often a corroded pipe in the manifold allows combustion gases to enter the piston cylinder via the MANIFOLD HEAT PASSAGE in the picture.

Then the cylinder gets carbonized and the piston can't move and locks up the choke plates....I've seen them so bad that I've had to use a brass brush and Hoppes #9 gun cleaning solvent to scrub out the cylinder like cleaning a rifle.

If you disconnect the choke linkage and go into the round housing and can't move the piston lever, that's your issue.

If you're on the east coast you can send the carb off to daytonaparts.com, I've used them for years and know Ron and Tim (owners) quite well.....they'll fix you up. If that manifold pipe is indeed corroded allowing combustion gases into the choke housing, that will need to be addressed also.

This picture is from an early Corvette carb but the piston (red arrow) operates on the very same principle: