[wtenglish]

I haven't personally installed a lower unit but I watched the mechanics replace one on a Yamaha 250 Saltwater Series after it crapped out on the way to the Bahamas two summers ago. To the best of my knowledge it only involved removing about 4 bolts and sliding it off. After that experience I wouldn't have any reservations about trying it myself if I was in your position. One thing I would need information on would be the proper lubrication level in the unit itself.