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Old 09-28-2020, 01:40 PM
Senior MemberCaptains Club Member
Join Date: Oct 2003
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Originally Posted by christuna View Post
I don't know what to believe in anymore. I guess i'm just gonna have to buy it and find out for myself I guess.

I've been watching speed tests of small boats with outboards on youtube and here's the "data":

40hp Yamaha: 33 mph / 4 Gallons per hour = ~ 8.25 MPG

10hp Mercury on a 16' boat: 19 mph / 1 Gallon per hour = ~ 19 MPG (!)

But then I read about horror stories like yours:

Correct me if I'm wrong but here's what I gather from your data: 35 miles / 15 gallons = ~ 2.3 MPG

That's appalling.

Of course it all depends on the state of the engine, timing, reed valve? etc...

I also checked the method of dividing the horsepower by 10 to get the consumption at wot and the g/kwh figure looked good.
modern 4 stroke engine will get much better fuel economy. Old 2 strokes (mine was a early 1970's model) won't get good economy. If the engine is a 2 stroke, the best thing you could do is sell the engine it has and get a brand new one.