How did you know the tab was broken off, or did you break it trying to bend it to get more lift. I've never been able to do that, they always break. If you don't have a working ACR, I'm leaning towards Jmechs thinking of its not spinning through compression fast enough to crank---at least I think that's what he is thinking.
Silly idea, but if your ACR is broken and your battery is weak/small..... Of course this is assuming everything you had apart has been reassembled properly.