Re: pump housing,impeller & key
The pump housing is shot, the impeller is unuseable (unless you like to be towed into port), but the key is reusable. They all get a slight "wear" mark form riding against the shaft slot and impeller.
With your pump body in that bad condition, check the walls of the lower plate that seals the lower unit. If the walls are corroded to the point where the stainless plate and gasket below the pump will not seal them, then it is time to replace it and the drive shaft seal too.
