Just did a full rebuild on my gas Westerbeke sea water pump. Everything but the pump body. Replaced the impeller 3 or 4 months ago and not seals. Seals started leaking, so decided to rebuild all of it since it had 1300+ hours on it. Hate to say it, but the genny generally gets way more run time than the big motors. Piece of mind as well since we often leave the boat unattended with the genny running if at a dockside restaurant. My 3 month old impeller had already slung off a blade.