While I'm sure this subject has come and gone before, with normal routine maintenance following annual best practices etc etc etc. And assuming reasonable care when operating, how many hours of life should this motor last before needing a major overhaul?
As I search for a new to me used boat.... There's a fair majority of 15 to 25 year old boats with four to six hundred hours on them where the motors have been replaced or rebuilt. So, if I find a boat with the original motor and drive and 750 hours..(which I have just found one)... That seems like a red flag. Yes a mechanical inspection can run a compression check without tremendous effort.... But isn't it really just a crap shoot at the end of the day?
I get a season or two maybe...then it begins to eat oil or the drive get noisy....
Can you really draw a line?
I welcome your comments and thanks very much!

Somewhere between about 600 and 2000 hrs It really is crap shoot, but I'd guess most average about 1000 hrs.
BTW, I have 502mpi's with about 700hrs on them and never done anything to them except normal maintenance stuff.