Hey Mr Rolla! How's it going?
If your other engine is a similar size from the same maker then it should fit. eg: I've got a Force 21 pull start that fits force 25 motors also.
I don't know if it fits a Force 17, in fact I didn't know there was a Force 17, but your happy to try it out if you want, since I blew up my Force 21 motor anyway.
I'm after $20 for it, but if you can find it for $30 or less then I'll drop my price!
Cheers, Oggy.
p.s. I work in Parramatta if it's easy enough to meet up & try it out.