Is outboard power determined at crank or using prop thrust. I'm aware car and motorbike bhp changed from wheel to crank but is that the case for outboards?Essentially is my Neolithic Mariner 30hp stroker putting out the same power as a spanking new 30hp Honda four stroke. Obviously taking age into account
Willk, so transmission losses are 10%?An old 30hp will be at crank and new ones are at prop. Meaning that the new 30 is more powerful than the old 30.
As for compression losses there is no smoke and if anything the unit will have loosened itself over time. But I was ignoring the ageing of the engine just wondering about what you answered in your first sentence.
The 30 hp deux temps Mariner is a peach of an engine.... Yamaha of course. And weighs nothing.
new outboards are rated at the prop and older engines were rated at the power head but sorry I dont know when this change was made.
like all engines they will also lose HP over time. I know it is slightly different but there are a few top gear episodes where they have taken sports cars that are 20+ years old and retested the HP and found it to be a lot lower i.e. more than 25%
It's normall to lose some compression as years of use passes by. Applying power tunner as directed on can every 100 worked hours can make wonders revitalizing old 2 stroker engines. That's if you don't usually use aditives mixed along with fuel.