Horsepower rating for older boats?

[CaptainPuget]

I have a 1980 16’ Hewescraft River Runner that I’m looking to re-power. It is rated for 80hp but as I understand it hp rating in 1980 were at the engine, today they are at the prop. Do I have to reduce the 1980 rating by some factor?

 

[JB]

Re: Horsepower rating for older boats?

I don't think so, CP.<br /><br />I suppose if you want to get really technical today's 80hp is "bigger and heavier" than a 1980 80hp, but I would call that difference trivial.<br /><br />Actually, the selection of 80hp engines today is very limited. If I were repowering a 1980 boat rated for 80hp I would probably be looking for a late 80s-early 90s JohnnyRude 70 triple looper* or a late model JohnnyZuki DF70 EFI 4 stroke** to repower with.<br /><br />* Three cylinder, 70hp Johnson or Evinrude loop scavenged 2 stroke.<br /><br />** Four cylinder, 70hp Johnson or Suzuki EFI 4 stroke.<br /><br />Good luck.

 

[CaptainPuget]

Re: Horsepower rating for older boats?

I should have added that I’m looking at jet outboards to complicate matters, particularly the Mercury line which offers 80hp, 65hp & 40hp – which have the same engines that they put on the 115hp, 90hp and 60hp prop models respectively. Since these don’t exceed the 80hp rating of the boat, are these are all “legal” options?

 

[JB]

Re: Horsepower rating for older boats?

I would call them legal, CP. If it says 80hp (or less) on the engine title it meets the boat's rating.<br /><br />Good luck.