I have a murray ride on with a briggs and stratton 12.5 that blew up and I have replaced with B&S 13.5 power built intek model, there is extra wire going to the carbie that was not on the old engine, and the engine does not seen to have any spark to start, do I need to connect this wire to ant thing?

The old engine had a fuel solenoid,
The new probably doesn't.
Just tape the end up and put it up so its out of the way

It's the new engine that has the wire is that for the carbie, is there a solenoid that needs to be triggered in there, or is it just for a warning light?

Yes it will need to hooked up so when you turn it on there's power there.
Luck

Thanks for your help, I hooked up the 12v and it goes like a charm.