I have a Troy Built with a 14HP Briggs engine, the original engine blew a piston and had to replace the engine. I found an older 14HP Briggs almost identical to the one I had. I got the engine in and tried to start it and nothing. When I jump the starter solenoid directly from the batery cable to the starter wire the engine turns over fine. The original engine had wires going to the carb float.
Not sure if I am missing a safety switch someplace or what might be the problem as to why there is no power when I tun the key.

Hi,
It is rare that you find identical engines on machines of different makes. It is obviously an electrical connection problem. They are almost impossible to diagnose from afar. They make lots of people pull their hair out in person. I attach the Briggs alternator/engine wiring guide for your perusual.
Peace,
Clarke