Old Vs New

[Northern Tim]

Guys,
I'm after buying a used 30hp outboard to replace my worn out, old 25hp Evinrude. I've been told that a 25hp engine built prior to 1995 will only give me about 18-20hp at the propellor, whereas a modern engine will give me 25hp at the prop. Is this correct?

I'm wanting to up the engine size so I can tow a wake boarder. Would a 25hp Yamaha autolube on the back of a 3.5m jockey console rib do the trick?

Cheers,

Happy Easter!
Tim.

[BogMonster]

I don't know the answer to your question but as somebody who deals in mechanical things a fair bit I'd be astonished if anything is 100% efficient! unless the ratings have changed from "engine rating" to "prop rating" if you see what I mean

[Nos4r2]

Originally Posted by Northern Tim

Guys,
I've been told that a 25hp engine built prior to 1995 will only give me about 18-20hp at the propellor, whereas a modern engine will give me 25hp at the prop. Is this correct?

The HP ratings were changed earlier than that but you're correct-Mercury went over to prop-rated HP in around 1988 and sold their old style 50's as 45's. Not 100% sure when Evinrude/Johnson did but definitely before 1985.

Bear in mind that stated horsepower is only a guideline and can has to be within 10% of what is stated on the cowl so a 30 could be from 27-33hp. Essentially, do your research thoroughly...

[mdt]

Originally Posted by Northern Tim

I'm wanting to up the engine size so I can tow a wake boarder. Would a 25hp Yamaha autolube on the back of a 3.5m jockey console rib do the trick?

might well do I have manged to tow a kneeboard with a 25hp 4stroke on a 4.3 rib??? but my son is only about 8stone.

borrow a wake-board and see what happens.