Classic/Antique Car Repair: trouble setting idle correctly, ford ltd, 351w

Question
Hi i have a 1970 ford ltd with a 351w and a 2 barrel autolite carb. The problem i have is i cant get the idle speed set properly. My dad and i had it set a little high at about 1000rpm the book says around 500-700. The porblem started when i took it out of park and backed out of the garage it ran perfect but all of a sudden the rpm went up to about 2000 and stays there in gear and in park.

Is there something im not getting adjusted correctly or is this just something simple? Thank you for your help
Steve

Answer
Sounds like the high Idle level from the choke jumped up on you. It is usually attached to the choke, but not always. You can find it with the engine off and the throttle level held open. Move the linkages around until you find the one effecting the throttle return.