All modern jet skis use an axial jet pump – a tube and nozzle setup that sprays water out with great force.
The jet ski pump consists of a housing, wear ring and impeller. The wear ring can be either plastic or stainless steel, depending on the make of your jet ski.
The jet ski impeller fits tightly and spins inside of the wear ring, which sits inside of the housing.
The jet ski wear ring and the impeller are the two parts that generally wear or are damaged. And are generally both replaced at the same time.