Nottingham spacedeck motor - driving me crazy

Are you changing the position of the belt to go to 33 1/3? Really it would be impossible for the table to only spin at one RPM as the pully has two different diameters, the smaller one for 33 1/3 and the larger one for 45 rpm. When moving the belt on the motor pulley, change it's position on the platter to keep things even.

Many thanks. I know it sounds impossible, but I initially thought it might have been due to different tension in the belt between the two speeds. Now, however I believe its the actual motor. Reason being, if I remove the belt, the motor will spin BUT on second attempt it does not. If I then move the motor slightly up or down i can get it to spin once or twice but then not again until I move it slightly up or down again. By doing this, with the belt connected, i can eventually get the platter to spin at 45. BUT no matter what I do it will not spin at 33.
Do you know where I could obtain a new motor, or is there some maintenance I could perform on the motor. Thanks again.

The most insane solution!!!! I replaced the belt with a piece of string and the table now works perfectly!!!!!!!! I guess the problem was the belt!!!!