Mercruser 5.7 Costs

[bendyone]

Hi

We have a Cruser 26 with a single 5.7 mercruser. How much petrol will it use firstly on the plane and secondly crusing 10 - 15 knots.

We used the boat for 3 house mixed motoring and the on a boat yard for 2 months in France, the tank was the empty when we last visited, 250l put in at the start. Was the fuel nicked while ashore??

Thanks

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[theguvnor]

Nearly 100 lts per hour seems a tad excessive

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[jhr]

I think your fuel has been “evaporated” by a person or persons unknown..

Have a look at <A target="_blank" HREF=http://www.boattest.com/test-results.aspx?ID=562&lg_username=&from_gi=Yes>this link</A> which shows consumption at various rpm for a 27 ft Maxum with the Merc 5.7. Bear in mind that the “gallons” shown are US Gallons, which are about 0.85 of an Imperial Gallon

It depends what you mean by Planing speed – as you will see from the tables, the engine drinks most gas per mile when the boat is just up on the plane at about the 2,500 rpm mark but, assuming you were using about 10 US gph at 15 knots, 3 hours’ consumption should have used up about 115 litres, if I’ve done my sums right.

So, either your fuel gauge is hysterically inaccurate (which is entirely possible) or somebody’s been doing a bit of syphoning /forums/images/icons/frown.gif.


<hr width=100% size=1>Je suis Marxiste - tendance Groucho

 

[neale]

WOT could see as much as 80 ltrs per hour being used. Economical on the plane cruising will be more like 50 lph. 10-15 knots will be a very uneconomical speed as it will be way beyong the hull displacement speed but not quick enough to be fully planing. Some fuel will evaporate while ashore and fuel guages on boats are notoriously innacurate.

N



<hr width=100% size=1>When I read about the evils of drinking, I gave up reading

 

[Chris_d]

I'd suspect your fuel gauge, when mine says empty theres still 10 gallons left and it only holds 40 full !! Handy for keeping a safe reserve though.

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[gjgm]

unless it was very specific trip, i think we re all pretty poor at timing engine hours.
Bit in the marina, bit anchoring etc. Sure thats not the most heavy use of fuel, but just how sure are you about 3 hrs? If so, then 250l for 3 hrs engine use is pretty thirsty going.. headseas? Id broadly go for 30-50l p/hour . But fill up the tank... maybe theres 75-100l still in there. Nicking while ashore.. dunno seems either very organised or bit of a pain for a few litres....

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