A DYNO test is usually for troubleshooting unique problems. If I were in
your position, I would ask for a compression test--a long max power run in
the lake and 20 minutes at fast cruise power--proof that the overtemp
sensors worked--a throttle-burst test or 2 as in lifting a skier--and a
gearcase pressure-test. If you want more than that--buy a new motor.