just bought one of these 2nd hand for my son

Can anyone tell me the part # for the throttle limiting screw, from the schematics it looks like 0451788 but it’s hard to tell and should also be a jam nut there right? Both are missing on the one I bought

Also, is there an aftermarket kill switch/tether for the rear of the quad so I can run behind him and pull it if needed? I have seen the ones for the 2 strokes but not the 4 stroke

Thanks!