Honda GCV 160 on a Yard Man mower

guy dropped it off, said he tried everything, cleaning the carb, new fuel, new spark plug all that, and it wouldnt start. so i tried all of the same stuff and it still wouldnt start. finally i decided to pull the cam cover to see if the belt came off or something, which it didnt, but i found that the lock nut for the adjuster was missing, thus the rocker was not opening the valve