[tsubaki]

I've had them leak all over on different engines between the foot and lower exhaust housing and not to seem to affect the cooling. Several models have a hole that pisses almost into the boats drainplug. Don't be tempted to add silicone, especially at the pump housing location unless the repair instructions state so.
Usually a hose connection will not let the engine get up temperature effectively to completely check the cooling system. You will have to get in the water.
Generally when I replace one on an engine I've had no experiance with, I'll replace the entire pump housing and all also, so as to have no question about correctness.
It's rare to have an unnoticed split in the tube to the powerhead and most people can feel when the tube is lined up properly when assembling.