2000 24 WA - Yamaha 300 HPDI Repower

[CJ Grant]

Here are the current stats from last winters repower project:
New in crate 2005 Yamaha 300 HPDI, 25" shaft replaced the original 2000 Mercury 225 Optimax. Added appr. 30# of motor weight and another 12# for bigger oil tank to gain the 75 extra ponies.
2000 24 WA - appr. loaded weight 6000#
138 gallons of fuel
5 gallons of  2-stroke oil + 2 extra gallons
120qt ice chest with 80# of ice
48qt ice chest with 20# of ice and full of beverages
5 rods & reels, 2 tackle bags, 25# of lead weight, normal amount of "necessary gear"
1 - 220# captain, no crew
Prop - 4 blade, 19P x 14.5" Mercury Vensura
Head Sea - 1' - 2' chop, 6-8 mph breeze
WOT - 5000 RPM - 39.90 MPH - 20.80 GPH - 1.92 MPG
          4500 RPM - 35.50 MPH - 17.70 GPH - 2.01 MPG
          4000 RPM - 28.80 MPH - 12.80 GPH - 2.25 MPG
          3600 RPM - 22.20 MPH - 10.80 GPH - 2.06 MPG
Beam Sea - 1' - 2' chop, 6-8 mph breeze
WOT - 5200 RPM - 44.70 MPH - 19.80 GPH - 2.26 MPG
          4050 RPM - 32.40 MPH - 13.20 GPH - 2.45 MPG
          3500 RPM - 24.80 MPH - 10.00 GPH - 2.48 MPG
Yami cruises nicely at 32.5 MPH with no trim tabs deployed, think I have a keeper!
I tried to run the 21 P prop that Yamaha had on their performance test site, but couldn't get high enough RPM's

[231CALIFORNIA]

with 4 blades that 19" pitch prop sounds about right.

If you are at 5200  now you will get even higher rpm when the fuel runs down and the ice melts(if drained and not replaced by fish). now you can comforabley cruise at that 32+mph chop allowing.

have you ever weighed your rig on a truck scale? just curious.

[CJ Grant]

It's on the list of things to do, Mike C confirmed the 6000#, but I need to find out for sure.
The 4-blade made a huge difference in the performance, with the extra traction and stern lift it basically levitates out of the water on plane, first time I've ran a 4-blade but so far I'm really impressed. The other nice side effect is that I can keep the boat on plane down to around 21 MPH with all the gear, kinda nice when it's a little lumpy out and you want to keep your kidneys where they belong.

[Dog]

  JC Grant
      5000 rpms. dose not sound like its enough. What are the max rpms. on the 300 yamaha. I thought most 2 strokes ran better around 6000 rpms. Am I missing something.

  Dog

[CJ Grant]

This is a 2005 Yamaha, the range is 5000 to 5500 RPM's, the newer model HPDI 2-strokes go to 6000.
It should be a touch higher, but I don't want to go down another pitch, lose to much top end & fuel economy.

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