I build them with 2 X 4 drilled & bolted together.
You could even buy and slightly modify a engine hoisting stand. Harbor Fright used to sell great cheapies. That lifted any car V 8 engine.
At least a 15 minute test ride some at WOT. Then a stop at dock and several restarts.
Might get lucky. Have to be real lucky. Depending where in the country the boat was .docked
I always make sure the grease or oil is fully covering all the inside and outside of the seal surfaces. Same with the shaft surface. Wipe it all around any metal surfaces the the seal must slide on to get into the correct place.
I prefer wires that have a fully MOLDED on sparkplug boot. It is easy to pull at a bad angle on the sparkplug boot in tight spaces. That can ruin the connector tightness in the right angle boots of the NON-MOLDED plug connectors.
Any seals that need to hold against ....Positive Pressure and Negative Pressure ( vacuum ). The seals MUST be placed in a certain way on the shaft.
I forgot the most important thing. The shaft bearings MUST NOT have any wear that allows shaft wiggle.