How to improve gas mileage

[edgewater1]

:eek2:I'm trying to figure a way to improve gas mileage on my boat edewater 170 CC, with a 90 HP yamaha 4 stroke. Trim, Weight Movement.

EW link: Edgewater Boats (http://www.ewboats.com/boats_performance.cfm?boats_id=5)

[WildeOne]

You should start by getting the setup right. Most dealers rig motors too deep, which is a drag producer. Move the motor(s) up one hole at a time until you get some cavitation in tight turns, then back down one hole. This process is always an empirical one. After that's right, make sure the motor is propped right (at the top end of the operating range. Once those thing are completed, make sure you have a fuel flowmeter such as FloScan installed and find the best engine operating point (RPM) for peak mpg and trim angle for max speed.

I repowered my boat several years ago and the dealer rigged the motors as deep as they could be. Dealers do this knowing there is zero likelihood of getting cavitation complaints. They now are three holes higher and fuel economy is up 20 to 25% (and top speed increased few knots as well).
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Jim
23' Grady White Gulfstream "Get Reel"
Ocean Pines, MD

[joe sportsman]

What you have is probably one of the most economical rigs out there! Probably won't be able to improve on it very much! I had a Keywest 17 CC and boy I sure miss it now! This F250 Yamaha is thirsty!
DB

[WildeOne]

What you have is probably one of the most economical rigs out there! Probably won't be able to improve on it very much! I had a Keywest 17 CC and boy I sure miss it now! This F250 Yamaha is thirsty!
DB
That may be, but you can't assume the motor is set up right.

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Jim
23' Grady White Gulfstream "Get Reel"
Ocean Pines, MD

[edgewater1]

this is great

TOny

[jobob]

Motor height will affect speed and milage, get a good wheel on there (nice double cupped ss prop), and keep raising the motor where it will not vent on turns. You might be shocked on how high you can go with the motor setup.

[DaddysGirlToo]

Slow down!

[WildeOne]

Slow down!
Not entirely true, unless you mean trolling speed. Most outboards peak in MPG ~ 3800 to 4200 RPM, not really slow for most boats. This is where a fuel management system pays off, in allowing you to find the peak MPG throttle setting quickly and for differing loads,

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Jim
23' Grady White Gulfstream "Get Reel"
Ocean Pines, MD

[DaddysGirlToo]

Sorry, I was being facetious