yup, i had exactly the same engine.
the compression is bob on from memory and certainly bang on difference limits allowed.
i assume you mean a flow sensor which apparently is this (need serial number to be 100%)- http://www.suzukimotorcyclespares.co...e%20temp?uID=0
fixing the gearbox may prove difficult, what exactly is wrong? was it ever ran with water in there? new prop and water in gearbox says to me the prop was smacked and that could mean the shaft seals are the issue which potentially means the shaft is bent. i would put a dial gauge on it before you do anything just to be sure.
i have lost a gearbox before with water intrusion whilst at sea and it isn't fun nor cheap so please do your homework to avoid what happened to me.