Hi Mark, as others have replied to your post, pictures will help. Our 1991 boat came with a MDKD three cylinder Kubota diesel model Genset. The sea water pump and inlet hose are on the port side of the engine next to the oil filter. The outlet hose that connects to the riser (mixing elbow) is on the starboard side. Once you locate these two hoses, a simple matter of inserting the inlet hose into a bucket of water and ditto the outlet side. You should see a good flow of water going into the outlet bucket once the engine starts and runs. If no flow, shut the engine off and trouble shoot.
Described above is for a cooling encapsulated engine where the system uses a heat exchanger for cooling. Yours may be different by drawing sea water directly into the engine and discharging through a discharge port, absent a heat exchanger.