Merc V8 fuel consumptiom/

[drewstwos]

HI all

I am toying. as previously posted with moving up a notch to a newer boat. currently the bayliner 2556 command bridge ticks most of the boxes. However, search as i might I cant find any fuel consumption graphs or info. So please..... Very approximately what would a 250hp mercruiser use per hour at idle, slow speed (under planeing ) medium. (Just on the plane) and flat out. The speed range is about 0 to 25 kts.
I know there are so many variables, so accuracy is not necessary.. just a ball park figure to give me someething to think about.
Thanks in advance.
Drew.

 

[merlinwasp]

Hi,

I found this a few months ago and may help. The formating is all to ............. but then this is advanced IT to me /forums/images/graemlins/ooo.gif

Test Power: 1x250-hp MerCruiser 5.7L Bayliner 265 Cruiser
RPM MPH Knots Total GPH MPG NMPG Range NM Range dBa
650 3.7 3.2 0.8 4.87 4.23 329 286 61
1000 4.5 3.9 1.4 3.21 2.8 217 189 66
1500 7.4 6.4 2.5 2.96 2.57 200 174 68
2000 8.9 7.7 4.5 2 1.74 135 117 69
2500 10.9 9.4 6.6 1.64 1.43 111 96 75
3000 19.3 16.8 8.8 2.19 1.91 148 129 77
3500 25.6 22.2 9.7 2.63 2.29 178 155 78
4000 31.9 27.7 12.3 2.6 2.26 176 153 80
4500 37.4 32.5 16 2.34 2.04 158 138 85
4850 40.7 35.4 20.6 1.98 1.72 133 116 87


MW

 

[gjgm]

that table supports what I was going to say,10-12ghp at cruising, 25knt.
Ball park figure 50 hrs a year(not all at cruising speed or you ve gone a LONG way!)£1250/1750 fuel bill.

 

[silver_boy]

A friend hooked his 7.4 300hp Merc up to a diagnostics kit recently and it was using 6 litres per hour at idle. Can't remember any other figures.

 

[ported0]

I have just got an EP10 fuel flow meter to fit to my 7.4l Merc will report back with usage figures as soon as it is fitted and tested, could be a weel though.

John

 

[neale]

Assuming we are talking about a 5.7ltr with carb:

WOT you will be using something like 17gph. For that boat, WOT will be around 25knots.

At 3500rpm ish you will be using something around 12gph but may only be making around 18-20 knots.

Fuel flow meters for petrol boats are pretty cheap and easy to fit and will save money by finding the most efficient speed and rpm setting.