Here's one for you:
http://www.yamaha-motor.com/products...triumph/bullet
in_otb_4StrokePerf_MidThrustJetPort_115hp_03-48-TPH-C.pdf

Best economy is at 1000RPM (4.3mph): 10.33mpg

At 1500rpm (5.7mph) : 6.7mpg

At 4000rpm (27.2mph): 7.22mpg

The Powerboats Report article doesn't list mpg below 1500rpm, where, for a
four-stroke, you get the best efficiency.
On two-strokes, it could be very different. I'll check later.



"Gould 0738" wrote in message
...
Mileage at 1500 rpm (6mph): approximately 6.2mpg
Mileage at 2500 rpm(9mph): approximately 3.5 mpg
Mileage at 3000 rpm(25mph): approximately 6.5mpg


TILT!

(occurs to me you kids don't fully appreciate that term).......

The performance curve seems out of whack.

The boat travels 6 mph at 1500 rpm.
Seems really slow, but let's use that.
It ought to do 6mph at a fast idle, one would think.

2500 rpm is only 9 mph? Still seems really, really, really slow, but let's
use
that.

If 2500 rpm is propelling this vessel at 9mph, it stretches the
imagination to
consider that adding 500 rpm will increase the speed by a factor of 2 1/2
times, or an additional 16mph.

Not saying it isn't so, just that it seems very unusual.

Sure the 2500 rpm isn't 19 mph, instead of
9?