I got the motors a few weeks ago, and was running it with 15 1/4 x 17"
props. That was too little prop for my boat (it ran the motors to 6100 rpm
and 43 mph)


At the 10 hour service after break-in, I repropped to 19" pitch.

Performance is phenomenal. Who says that the new four-strokes don't pack the
punch of the 2-strokes?

Top end is between 46 and 47 mph at 5600 rpm...and that's with full
eisenglass up, 3/4 fuel (1200+ lbs), generator, and 5 people plus gear.
Mileage was an astonishing 1.1-1.2 mpg at WOT. The older 250 OX66's ran
that boat to 43 mph, but only got about 0.7mpg at WOT.

Most economical cruise speed is anywhere from 3800rpm (28mph) to 4400 rpm
(34 mph)...yielding about 1.5 mpg.

At trolling speed, fuel burn is half what the 2-strokes burned. And at
"just-on-plane" speed (18.5-21mph), the new motors get 1.3-1.4 mpg...and the
2-stokes got 0.8 mpg.

Did I also mention that I can carry on a full conversation on the cell phone
while running WOT?

I figure these motors will save me about $2,000/year in fuel/oil
costs...which pays for the extra $140/month in my payments. When you add in
the extra cost for insurance, though, I break even. Still well worth it
considering the warranty, and the pleasure of no-smoke and quiet operation.








"NOYB" wrote in message
ink.net...
The port engine on my Grady quit running while heading back in last week.
The problem was diagnosed as a faulty low pressure fuel pump. It's a
pretty inexpensive part, so I told the dealer to replace it and the five
other ones as a precaution.

But that same day, the owner of the dealership called to pitch me on
four-strokes. With my old motors as trade, and reusing my existing gauges
and binnacle, it became pretty cost effective to replace the old
two-strokes. I figured that the fuel (gas and oil) savings alone should
be about $3-4000/year. But more importantly, I'm going from a 5 year old
motor with no warranty, to a brand new motor with a 3-year warranty.

I may not keep the boat the 7 years it would take to recoup (in gas money)
the additional cost of upgrading. But if something major went on the
two-strokes in the next couple of years, I'm way ahead with the new
engines. Also, if I sell the boat in 4 or 5 years to upgrade to a
different boat, I figure it would be much more marketable with 4 or 5 year
four-strokes, than 9 or 10 year old two-strokes.

I'll be sure to post performance data on the engines vs. the old ones once
I get past the break-in.

The new engines are twin Yamaha F250 four-strokes.