how many HP has a 10HP outboard?

[Inselaffe]

My 1999 Yamaha 9.9 HP 4 stroke is said to produce only max 8HP at prop (Clymer Manual).

I understand that there are shaft etc losses between engine and prop, but when an engine is quoted by the manufs as X HP is this at prop or engine?

I think I can vaguely remember someone saying that they changed the rating at some specific year from at engine to at prop?

Thanks

Leigh


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[duncan]

as I understand it the actual quoted HP will often be a result of marketing - an dthis can go both ways!
eg generally they will want to quote the max HP (crankshaft) for any given weight/fuel consumption etc but there are many instances where local regulations, taxation etc influence them to market below a particular threshold - and 10 is I believe a common one.

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[Kevin]

Hi

I as far as im aware the crank - prop rating was changed early 80's, 82/83 this was for the major manufacturers on the larger engines.

Kevin