Scott this is for you or anyone else experiencing this problem. I dove into this a sI could not find anyone to help me. I have a 1934 B&H Filmo 8 which was doing the same thing. Turns out the take up reel gear inside the arm is actually clutched to allow slippage. The gear is sandwiched between to washers and between the washers and the gear were two thin cork discs which were all stuck together and not able to provide the slippage needed. I took the gear out and carefully heated it to melt the old grease and then separated the pieces and cleaned it all off and reinstalled the assembly and after letting it run awhile without a film in it started to do what it was designed to do slip! I have since watched quite a few films with flawless performance. Hope this helps someone else to enjoy these vintage projectors.
best regards, Brian
October 2016