Mercury. Miles per gallon

[jimbouy]

Daft Question with a lot of variables.

But I have a 4Hp Mercury 2 stroke.

I suppose the realistic question is how long might I expect it to run on a gallon of fuel.

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[Georgio]

I have a similar engine from Yamaha and it uses around 1ltr per hour so I normally get just over 2hrs motoring when using the inbuilt tank.

Hope this helps

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[aitchw]

That's about right, I think. I have a Mercury 4hp and use that as a rough guide. As you say, lots of variables. What's it pushing at what kind of revs?

Howard

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[jimbouy]

Leisure 17 at a sensible pace. Just wondering what is a sensible amount of fuel to carry, just incase, whilst solent pottering

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[aitchw]

I would imagine that it would give you 3/4 knots in slack water at around half throttle so pretty economical. I would want to got out with a full tank and a 5ltr can but that's just my questionable opinion.

Howard

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[duncan]

answer = 2.5 hours at full throttle

was that the question you really meant to ask?

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[jimbouy]

I think it is probably the only question with a definative answer.

I suppose It would be useful to know what kind of speed to expect my Leisure 17 to achieve with said OB in slack water and no leeway.


Jim

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[duncan]

ah there are so many questions! and even more answers!

However -
(1) forget theory and go out in the boat, open up the throttle and (assuming slack water, across tide or whatever) establish maximum speed through the water.
(2) for a displacement hull (debatable whether this will act in that way and somewhat dependant on crews weight!) you can then work out the likely relationship between speed/throttle/ consumption from standard graphs - eg. 40% throttle = 65% revs = runs for 5 hours on a gallon.. If you have a rev counter linked to the engine great - but I doubt it!
We could do a whole lot of theory here but as we are not talking about a one off mission to mars (?) I really would just go out there one weekend and establish what really happens with your rig.
ps if your problem with this is you don't have a 4hp Mercury 2 stroke but were thinking of getting one let me know and you can borrow mine!

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[aitchw]

And then again there's engine condition to consider (old, dirty plugs etc.).

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[duncan]

surely not a factor on any self respecting forum member's boat?..../forums/images/icons/smile.gif

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