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Old 16 July 2016, 15:06   #11
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Ok, thats perfect and think gives the knowledge I have an issue although going to do a 20-30 mile run tomorrow morning and get some breakfast in yarmouth and run back to give me a definitive answer.... Full English or Bacon roll depending on the gauge when I arrive!
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Old 16 July 2016, 16:23   #12
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2.7L/Nm is the sort of return I was getting running 2 x 300HP Suzukis over 250 miles on a lad's weekend in Scotland on a 10m RIB.

You have a problem or the fuel barge is taking the p1ss...
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Old 16 July 2016, 17:17   #13
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Probably both!! Do people think the injectors would be the first place to start in the investigation?
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Old 16 July 2016, 17:35   #14
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I'd consider leaks too!
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Old 16 July 2016, 17:39   #15
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More and more worries!!!
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Old 16 July 2016, 23:32   #16
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I find this fuel calculator pretty accurate, I normally use it in littles but have clicked for gallons at the top of the page.http://www.boat-fuel-economy.com/suz...perial-gallons

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Old 17 July 2016, 03:14   #17
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Thats great and interesting, My cruise RPM at 25 knots is usually around 3500 to 4000 and that is doing upto 35 ltrs and hour... Then add the messing around bits, up and on the plane a few times as was messing around with another boat at one point, few circles and playtime Im not sure I am a million miles out but the longer trip to the needles this morning only happened in my mind as couldn't wake up! Another day to do a proper test!

The engine revs to 6000 within range but on the end, so another consideration might be to replace prop and pitch down a little to reduce RPM and help with Fuel?
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Old 17 July 2016, 03:37   #18
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its also worth considering whether "filled to the brim" is the same before and after. Slight changes in angle (e.g. people one board) can make a big difference to the size of any air pocket trapped in the tank.
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Old 17 July 2016, 03:41   #19
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True on the brim comment although the first time was on trailer and took ages to make sure it was full and second time on marina berth.. sadly think it is more likely less fuel in the second fill up!
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Old 19 July 2016, 01:14   #20
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My 200 cruises at about 1.0 to 1.1 l/nm. At the least inefficient I get about 1.7 but that would be just before getting on the plane. I think a 17 mile trip is a bit too little to accurately calculate consumption. Certainly worth a longer trip and at more constant speed.

Calibrating the lowrance software is a bit of a pain but does end up quite accurate if you do it properly. There is a guide on the net somewhere about which .luf file to use. Don't upgrade just for the sake of it as that can cause more problems than it solves.
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