55 Buick Loses Idle in Gear

All,

Question for you about one of my 55 buicks. My 55 Special, 264/Dynaflow, is losing idle when I put it in Drive. Just did a complete tune up and carb rebuild but it has always had a problem of the idle dropping and the engine shutting off or almost dieing when put in Drive or Low. It idles great in Park. To get it to not die in Drive or L, I have had to increase the idle speed and it is just to high in Park. Any ideas or thoughts as to the issue?

Steve

 

I'd think it was a state of tune issue but without actually seeing the car and digging out the magic screwdriver it's hard to tell you exactly what part of it is causing the problems.

Go back to the basics of it.

Is the timing set correctly?

Is the idle mixture set as close to right as you can get it?
The norm on that carb is to gently seat the screws and then back them out 1-1/2 turns as a starting point and go from there when the engine is running with a vacuum gauge.

When you rebuilt the carb did you set the float level at the exact level that the book calls for?

Vacuum advance working correctly?

No vacuum leaks.

Usually on something like that it is something that didn't get adjusted correctly or didn't

 

It's been a while since I had a 55 Buick so I dont recal if there is a switch or linkage to that controls the "switch 'pitch" converter. You might have missed hooking it back up and the converter stator is in high and loading the engine down. That's where I would start.

My buddy a 65 GS, it also had a switch pitch converter and we forgot to hook it back up when we rebuilt the engine. We had the same issue and it drove us nuts for a day till we figured it out.

 

'55 is too early for a switch-pitch converter, at least in production. Was there an idle-stop solenoid on that carb when you rebuilt it? If so, is it working and properly adjusted?

 

Mr48, Tbone, and Clay,

Good thoughts. I believe we have the timing, idle mixture and float all set correctly. I am thinking vacuum problem the way it is acting. It idles way to sweet in park so something is bogging down the engine when I put it in gear. I am breaking out the shop manual.

 

Vacuum leak. Break out a can of carb cleaner and spray around the intake to head mounting, carb mounting and vacuum ports... If the idle goes up- bingo!