On Apr 10, 11:48*am, wrote:
On Sat, 10 Apr 2010 10:37:13 -0400, "mmc" wrote:

"Tim" wrote in message
....
I'm familiar with two cycle motorcycles, and they're power band. Some
are really finicky and doggy untill you hit a certain rpm, then can be
almost uncontrolable. (Motocross) while some have less power yet a
wider range of usable torque.(Streetbikes) *and some have the tuning
at the absolute bottom of the rpm ranges (trials bikes)

But concerning a v-4 johnson/evinrude etc. Is there a powerband where
you run a set range *rpm for maximum efficiency? too little rpm labors
the engine, and too much gaines little except sucks more fuel?

Well, my experience is that just enough throttle to keep a boat on plane is
the most efficient (get somewhere) setting but this doesn't work for a
normal, round tube pontoon boat.

A pontoon still has a step where the hulls level out a bit higher in
the water than pure displacement. More speed generally raises that up
a little but at a pretty good increase in fuel consumption.
If the motor and boat are well matched it will be up on the step and
leveled out at 3200 - 3400 RPM. Bumping that up to around 4000 RPM
gives you a good cruise speed and a healthy RPM for a 2 stroke engine.
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Thanks Greg.

That's worthy of consideration.