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Old 17 September 2012, 21:24   #1
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engine question

Hello, I'm looking to power a ZODIAC PRO 20 with twin honda 150's does anyone have an accurate GPH rate for this combo? Thank you
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Old 18 September 2012, 08:43   #2
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Paddy,

Welcome to ribnet!

I can be absolutely no use here with a direct answer, but there have been numerous fuel consumption threads in the past. Have a search through the forum (the search engine is pretty good) ansd see what drops out.

As you are presumably thinking of going twin, be aware of the "perennial discussion" surrounding twin engines & economy..... There are some fairly strong views on the matter!

Having said all that, "accurate" fuel economy is a bit of a difficult one for boats - for example if you motored upriver all day, you would be drinking more per mile than going downriver with the "road" pushing you along too. Weight & it;s distribution, engine trim, hull shape & driving style are also big influences on fuel consumption. A good rule of thumb seems to be about 1L/ nautical mile as a going in point, regardless whether you have a 3L V8 on a 26' hull or a 2 cyl 25Hp on a 16' ......
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Old 18 September 2012, 08:48   #3
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I've missed something somewhere. Do outboards not return a fixed GPH at a fixed rev?

How fast the boat goes is another matter obviously...
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Old 19 September 2012, 04:06   #4
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Engine load will affect it.

Hence my comments on trim / balanc / weight distribution......

Somewhere on the net were some tests , although from memory they were Mercs...
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Old 20 September 2012, 21:37   #5
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to 9D280
Thank you very much for the reply and very sorry took so long to get back to you.
I'm aware of all of the above was just trying to find something to give the bank and the accountant (the "numbers" people they are) Thanks again. BTW love this site!
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Old 21 September 2012, 03:15   #6
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From a test of 150 hp outboards in a swedish boat magazine:

Boat used: Flipper 605 WA (6,15 meter x 2,32 meter, total weight at test 1400 kilogram, water temp 18 deg. Celsius

Honda BF150
Top RPM in test: 6000
Prop used: Honda HR, 3 blade, 20 inch pitch


b) Fuel consumtion (litre per nautical miles):
At max rpm: 1,27
Minus 500 rpm: 1,03
Minus 1000 rpm: 0,91
Minus 1500 rpm: 0,80
Minus 2000 rpm: 0,75


I know this is not your boat and its a single engine but sorry its the best I have.

Dave
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Old 24 September 2012, 10:10   #7
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Thank you very much Dave.
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Old 24 September 2012, 13:19   #8
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I've missed something somewhere. Do outboards not return a fixed GPH at a fixed rev?
Nope
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Old 24 September 2012, 13:59   #9
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Nope
I think you'll find that's "Yes" and "Nope" and
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Originally Posted by 9D280 View Post
Engine load will affect it.
But thanks for the assist anyway
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Old 24 September 2012, 14:18   #10
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I think you'll find that's "Yes" and "Nope" and

But thanks for the assist anyway

Uh Uh, deffo a nope to the original question!
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