i have a 61 Oldsmobile dynamic 88.
Problem is the “flap” on top of the carburetor is fully opening when I turn the ignition on. So the engine won’t turn on. If I hold the flap in the closed position then crank the car it will turn on but then I have to manually hold that “flap” to keep it from fully opening and dying out again. Is there a way I can tighten this “flap” so it gives the right amount of air/ gas mix going into the engine? TIA all.

 

The "flap" is called the choke plate, and apparently your automatic choke mechanism isn't working properly. A thermostatic coil is supposed to hold the choke plate closed when the engine is cold, and as the engine warms up this thermostatic coil expands and opens the choke plate. The problem could be a bad choke coil or it could be a misadjusted or improperly assembled choke linkage.

 

Have you pressed the gas pedal to the floor to "set the choke" before starting ?

 

Joe knows his sh*t, he's forgotten more than most of us know about Olds! ;p) Check to see if the choke plate linkage rod is attached to a coiled spring on the intake manifold, sounds like the choke isn't even hooked up.
GOOD LUCK! Post/let us know if this worked, we'll throw more ideas your way if needed.