I took the advice from a previous post in this thread: "finding a local shop that will give you an hour and go through the basics is my suggestion, get it started for you or diagnose why it won't, make a list of things that need done, if this is your first PWC its almost a given that you'll miss something that could be critical."
Just to get that heads up, and see what's up.
Turns out it is the starter
We did pull the plugs while I was with him, and we turned it by hand, and there was a slight scraping noise when turning, he said the bearings might be going
It did sit (says the previous owner) for 5months, is that sound normal?
Hopefully the starter replacement ($100 for the part+labor) gets it going to use a bit