2017 king quad 750 no start
 

i have a 750 king quad that has multiple codes after changing the fuel pump
no codes before changing it
c13 c14 c15 c21 c23
please help

I'm not at work to check what those codes are, but double check that you have re-connected all those wiring plugs that had to come off when you removed the rear plastic. Dead easy to miss poking one back through when you re-fit the plastic.

No start
 

You can try it, most of those codes are to do with the throttle body and sensors on it. You don't need to disconnect the throttle body wires to change a pump, but did you?

As I wrote earlier most of those codes are to do with the throttle body, so check the wiring plugs to do with these sensors. It is possible to get those pump motor and fuel gauge wires mixed up. I doubt if this would throw those codes, but check them. If all else fails, sticking it on the computer at the dealers should pin point the problem.