So, which one do you trust your computer or fuel gauge?

My new Suzuki 200 computer has been spot on for fuel usage when refueling at the pump during the 115 hours of use until last week.

When refueling at Roche Harbor on San Juan Island over the weekend, my computer says i had used 55.1 gallons. The fuel pump says it pumped 65.5 gallons. I'm not sure who regulates the fuel pumps but Roche Harbor Marina got about $50 more revenue than they should have from me. ($4.78 per gallon). stay away from Pump #7. it's evil.
Brett
 
ken35216":3gt6hk2f said:
.....but if the water is flat I'll kick it up to about 25 (4,100 RPM)
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Somehow I find it reassuring that even at 3000 miles apart you and I have settled on the exact same "sweet spot". I, in my 25 cruiser with a Yami 200, have found thru trail and error that when the water is relatively flat, my sweet spot is exactly 4100 RPM (at which I do about 25 MPH).

Two other spots I like are 1400 RPM for when I want hull speed, and 3600 RPM when I want the slowest speed (within reason) where I can stay on a plane without fuel consumption increasing. OTOH, these lower RPM spot might depend a great deal on the prop pitch (mine is a 15" pitched prop).
 
starcrafttom":29w7h7ge said:
3mpg? best I get is 2.5 with my honda 225. but my boat is heavier.
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I've got 150 hours on my 200 Yamaha and it's been consistent at almost 3 mpg. My 150 Suzuki was lucky to get 2 mpg. It really has been a pleasant surprise as I figured I'd loss a little mpg going with a larger engine :D
 
graph_data.jpg

The above is the table done on "Sea Weed" when empty. On sea trials, the gauges showed almost the same results....but this is 'light boat".

I would not be surprised if some of the boats get worse "mileage" with loaded boat for cruising. Interesting is that the higher speeds show better mileage--as some others have experienced with the 22's as well as 25's.
 
thataway":3b5zcsse said:
graph_data.jpg

The above is the table done on "Sea Weed" when empty. On sea trials, the gauges showed almost the same results....but this is 'light boat".

I would not be surprised if some of the boats get worse "mileage" with loaded boat for cruising. Interesting is that the higher speeds show better mileage--as some others have experienced with the 22's as well as 25's.
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STW (speed over the water)

You're always making me look stuff up! :D
 
I called Ray on that one when he first posted it. STW = Speed thru the water, but really should be speed over the ground. Speed thru the water is only measured by a paddle wheel or pitot tube device. I first believed that these were statute miles. However, the GPS reads knots. So I have to assume that the chart was recorded in knots, not statute miles. To affirm this you look at the NMPG= nautical miles per gallon....I have changed one GPS to statute miles, because most of the ICW and rivers are in statute miles...I leave one of the chart plotters in statute, and the other in knots! One nautical mile equals 1.15 statute miles. So the 28.3 Knots equals 32.6 statute miles per hour.
 
However, the GPS reads knot
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That all depends on how one sets up their display. You can change units in settings. As an example, I have my main newer Chartplotter set to show units in Nautical miles and Knots. However, I have my other older standby chartplotter set to read Statute miles and MPH. So I can report either at a glance of one chartplotter or the other. :) Also, if one is trying to get accurate data, speed thru the water is going to be more accurate than over the ground. At least then you can make corrections for current. Colby

Late note, just read your comment again Bob. You knew all this. lol. So I suspect you meant that with the data you presented, it's assumed that since you got the boat with the units set to knots, that is what it was at the time those numbers were recorded... :mrgreen:
 
Turns out computer was off by more. It said I had 29 gallons let and when I filled up I took on 90 gallons. Not good! It’s been perfect up till now which means I may have made an error.
 
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