150 Four Stroke, gearcase modification performance increase

[Wave to Wave]

After getting a custom nosecone installed, I decided to blueprint it to improve the performance. I rounded out the tip, and redid the edges of the skeg. We gained speed, and are now hitting the rev limiter with a 28" ProMax prop, 77 MPH at 5940 RPM. We are getting 6.75 MPG at 60 MPH. And over 6 MPG at 65 MPH.

Here's the write up on what we did, and a video too. Will try a 30" ProMax, and possibly a Hydromotive Quad 4 X OT, and should be able to get 82. This is why I wish the ProXS version of this engine came with a sportmaster and 1.75:1 gears.

Article: https://www.wavetowave.com/home/2019...cation-testing


[url=https://flic.kr/p/Rvo6rZ]Allison Merc 150

[Wave to Wave]

[12many]

dude. ...that thing moves

[Wave to Wave]

dude. ...that thing moves

Thanks, Not bad for a basic 150!

[Bamaman]

I'd hate to see that Allison with serious horsepower on it. It'd be scary fast.

[MacCTD]

That's awesome, what model is that Allison and what years were they made? if I wanted to duplicate that setup what would i have to spend for a hull like that? range? Thanks.

[Wave to Wave]

That's awesome, what model is that Allison and what years were they made? if I wanted to duplicate that setup what would i have to spend for a hull like that? range? Thanks.

It's a Grand Sport model # XS2003. They started making them in 1992 I believe, and still make them. This is a 2019. Used ones are good, because they are built extremely well. The boat is fully composite, and has a unique structure, making it super strong . If you found a used one, and got a certified pre owned Merc 150, or the new 150 ProXS, you could be in one for a reasonable amount of money. They do hold their value well, so you'd have to keep your eye out. New ones start from 40-45 with trailer, depending on options, but check with a dealer on that. My engine was a certified pre owned from a Merc dealer, full 1 year warranty, great deal.

I love it. The gas mileage is incredible. You can cruise all day and barely burn any gas. At lower speeds it is virtually silent in the cockpit.

[MacCTD]

Thanks for the info.

[Boondock]

Very cool rig
Just needs an open bow and a trolling motor