Re: Water bypass cover?
Are you speaking of the long strip of metal on the side of the gearcase? The water inlet screen is on the forward edge of the exhaust outlet snout, and a water passage is cast into the gearcase between there and the water pump. The bypass cover covers it, making a closed tube, so to speak, to the pump.
When running in reverse gear, the propeller sucks water away from the inlet screen, so holes in the bypass cover give it an alternate water inlet for when it is running in reverse.
If that is not what you mean by bypass cover, please explain.