Fuel Consumption on a 1990 9.9 Johnson

esteban14

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May 18, 2012
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Hello all. New boat owner here. Well, I say boat, but it is actually a 16ft inflatable so hopefully I won't be shunned. Plan to take it out into the 10,000 Islands of So Florida and need to understand fuel consumption. My short web research has yielded the following rule of thumb HP/10 for GPH at WOT. Therefore I should get something a little better than 1 gallon per hour. #1 does that sound about right for my motor and #2, at 3/4 WOT, what ballpark MPH will I be doing. I realize there is alot of variables but I am just looking for a range so I can plan how much fuel I will need for a weekend trip. Thanks in advance for your patience and comments.
 

Will Bark

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Aug 1, 2010
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1,470
Re: Fuel Consumption on a 1990 9.9 Johnson

I would still calculate the 1 gallon per hour and not telling what speed you would be going; depends on boat and load being carried. What ever you come up with I would double that figure; better to bring some back than run out. Good luck and have fun.
 

raczekp1

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Mar 30, 2010
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1,327
Re: Fuel Consumption on a 1990 9.9 Johnson

i run my 9.9 for 6 hours on troling speed,with 2 person and boat 4m long, weight 100kg and i lost 5L (1.5 galon) of fuel
 

esteban14

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May 18, 2012
Messages
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Re: Fuel Consumption on a 1990 9.9 Johnson

i run my 9.9 for 6 hours on troling speed,with 2 person and boat 4m long, weight 100kg and i lost 5L (1.5 galon) of fuel

Thx racz. Any idea what you would burn at 3/4 WOT? Does 4L per hour sound reasonable?
 

raczekp1

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Mar 30, 2010
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1,327
Re: Fuel Consumption on a 1990 9.9 Johnson

at 3/4 i think you will burn 2-3L per 1 hour
 
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