proper prop

[danlb]

I am one of the newest owners of a Defiance 220EX. The boat just had its first day in the water last Saturday. We ended up with a Yamaha Turbo 14 1/4 X 15R stainless ( part # MAR-14215-TR-E0) on our Yami 150, My early test with the trim close, but not quite completely optimized was 5700 -5800 RPM, 34-35MPH and 16.8gph at WOT. At 4200, we were at 27mph and 7.6 gph. Still more testing to go. The boat was light, with 2 people, very little gear, the Yami 9.9 on the back and 40 gal of fuel. But, the engine is just in its 3rd hour, so we should see improvements in fuel burn, and also I had to hold my testing to under 5 minutes. Even if it ends up no better than this, I'm extremely satisfied.

[tictactug]

Dan,

Not to hi-jack the thread, but where abouts are you located...and how are you getting your fuel burn info?

[danlb]

Jason, I am in Gig Harbor. I am getting the fuel burn info from the Yamaha speed-fuel gauge. Talk to Bo or Russ at Defiance. They will know exactly what I have, as I just bought it from them. It plugs right into the Yamaha network ports mounted under the steering console, and it's receiving data directly from the main engine computer, just like on today's cars. It's probably the one gauge you can buy that will pay for itself. Sometimes 100 to 200 RPM can make big difference in gph. Install is drilling a 3" mounting hole and plugging one end of the Yamaha network cable into the gauge and the other into the Yamaha network switch (which you already own, under your dash)

[tictactug]

Well...I have a little testing to do.

I jumped the engine to it's top mounting position, and the motor is running a little higher, and right where it should be in calm water (time will tell in the ocean....good or bad).

I ordered a prop from power tech. It's their offshore 4 blade prop in a 15 1/4 by 14P.

We will see what this does to the boat. I'm expecting a better hole shot, but will probably still be in the same rpm range at WOT (5,500). I currently have the factory aluminum in a 15p

If my hole shot is good and my midrange is fine then I will probably stick with it even if I'm only turning 5500 with a light load (two guys full tank of fuel).

If this doesn't work they make the same prop in a 3 blade, so I will swap to that. If that doesn't work....well the next step is to get crazy and have someone then try to mess with the prop.

I tried a Mercury Enertia in the 15p, and saw no real improvement over the aluminum, that's why I'm going to drop to the 14 to see what happens.