Troy Bilt Bronco 17HP Kohler to Briggs wiring

The Kohler 17HP bit the dust on my Bronco. I ordered a Briggs 17.5HP and have installed it. The wiring is completely different for the two engines. The new Briggs has a single red wire and a two wire harness with black and grey wires. The original Bronco harness has one each of red, white, green and purple wires(engine side). There is a orange wire that is looped back into the harness by the factory. Has anyone run into this combination of different wiring and if so what has to be done to make it run? Any help would be greatly appreciated before the grass grows knee high.

I’ve done a couple of these. Save the old Kohler plug to use for making a harness. On the Briggs the red should be dc output for charging the battery. The black is the coil kill wire and the grey runs 12v to the fuel solenoid. Been awhile so you may want to confirm that I’m correct. I use the old engine plug and wire it to the new engine. Plug the Kohler plug to the mowers harness....have wire stripped for testing with a meter. Turn key to run position and find 12v power source for the fuel solenoid and for charging. Turn key to off to find the kill wire by ohming out to a ground source. Splice wires in and your good to go. It’s a matter of tracing and connecting the wires and double check your work before turning that key.