Sorry about that. I guess I paid more attention to the first reply, than the original post

I'd have to answer "no" to your question... it shouldn't make the engine die. (In my opinion)
If anything, it should still speed the engine up, just as any sort of engine braking would do.
You might try switching props back. temporarily, just to make sure... but I'd doubt it.
I guess it might be "possible" that the new prop isn't revving the engine as much on your
downlines. Perhaps someone with a good handle on a formula for that might chime in.

I would've thought a larger prop would idle even better... due to greater "flywheel effect", if nothing else.