lmpellor replacement

[140boat]

Hi all just joined forum ok ive been given a nice 16ft haines hunter V16R with an old evinrude 140 V4 engine off my neighbour 2 weeks ago which was a score and im in the middle of doing a transum rebuild big job first time ok boat hasnt been in water or started for at least 6 years when igot it over home charged battery got clean fuel hit the choke and it fired first kick and ran like a dream even pumping plenty of water surprised me now just want to ask ive been told to replace impellor just to be safe can anybody explain on how to pls and is there anything else to replace before going out on its first run in a couple of weeks thanks

[boats.net]

Have to remove lower unit to replace water pump, need to change gearcase oil too.