Yamaha F15/F20 whats the difference?

[SundayMoney]

I'm going to buy a new Yamaha F15 or F20 in the next couple days. From the specs on Yamaha's site,the engines are identical. Same displacement,same gearing,same compression,etc.

If everything is identical,where does the extra 5 hp come from?

 

[JB]

Re: Yamaha F15/F20 whats the difference?

Everything is not identical. . . only the stuff they tell you about.

The book specs don't tell you about cam profiles, ignition advance curves, venturi area, compression ratio (?) or exhaust resonance (?).

 

[robert graham]

Re: Yamaha F15/F20 whats the difference?

Probably very minor differences in size, shape, location of transfer and exhaust ports and carb jet sizes. Good luck with your new motor!

 

[robert graham]

Re: Yamaha F15/F20 whats the difference?

My mistake, those are 4 strokes...I was thinking about 2 strokes...