Exmark Quest 24 H.P. B & S Engine to 20 H.P. Kohler wiring

Replacing a Broken 24 H.P. B & S Engine with a 20 H.P. Kohler Engine. How do I do the wiring?

You need to have both the wiring schematic of both engines and the mower to even start.

And you need the model number(s) also to find the schematic most likely

Before you pull the old motor take the blower housing off and tag where the wires go.
Magneto, carb solenoid, alternator etc etc
When you put the new engine in pull its blower housing and connect the wires to where they need to go
If the old motor is absolute toast then cut the plug off it with as much wire as you can then cut the plug off the new mower and splice the wires together according to where they need to go.
If you don't want to chop the plug off the use trailer wire take offs