All of the little motors are basically the same in form and function. Do a search on youtube, there are several step by step instructional videos to walk you through the process. I had never done one before and I was able to get through my 6HP Merc and felt comfortable enough with it that I did the 75 HP main motor the next fall. It really isn't difficult at all and after you do it once you will feel a lot better about what is going on in there. The only advice I have is to pay attention to which direction the fins are bent and rotating because once you take the old impellar out you can spin the new impellar in the housing in the wrong direction. The only issue I ran into was aligning the shift rod back up when putting the lower unit back together. No big deal, just took a little time to get everything lined up and bolted back into place.
Honestly, don't be afraid of it. Watch the video and take the thing apart, it's a simple job. After you've done it once, it is maybe a 15 minute job.
Give a man a fish and you can feed him for a day, teach him to fish and you will never see him again.