Volvo /OMC sea water pump 3858847. 6.5 inch pulley
Saw older post here by Sparkinator, it seemed to say you could change the shaft seal behind the impeller without disassembly of the pump(as long as bearings turn smooth).
Seal is. SKF Rotary Shaft Seal: 1 Lip w/Spring, HMS5, Nitrile, 16 mm ID...