I start mine up on the garden hose in the yard. Put 2 five gal. buckets. (one on each side of the wake plate where most of the exhaust water runs off) and idle it up to temp. Allows me to check that nothing is leaking (tighten hose clamps that I loosened during winterizing), makes sure the thermostat is going to open, as well as collects most of the antifreeze, Oil gets circulated, and the boat is going to run that first launch. Nothing like watching those that tow all the way, get everything loaded, and nothing works. (dead battery, bad connection, bad starter, etc).
2004 Supra Launch 22 SSV
5.7L Indmar Assault
"One More Hour"