nautica 10 ft jet boat gas consumption rate ?

[mick hodapp]

hello folks, does anybody on this forum know what the approx gas consumption rate would be at wide open throttle on my 500lb,10 ft nautica rib with the 80 hp, 2 stroke,yamaha inboard jet motor ?

 

[Scott Danforth]

your 2-stroke will burn 0.55 lb of fuel per hp per hour.

so if you use all 80hp and run it for an hour. gas weights 6.3# per us gallon (0.55 x 80 x 1 ) / 6.3 = 7 gallons of fuel per hour

 

[Silvertip]

That number is very conservative. My 75 hp merc on a 17 ft v hull will burn 7.5 gph and that number is from a fuel flow monitor. My "guess" would be closer to 8 gph.

 

[ahicks]

Easy to remember rule from way back I've always used to figure fuel usage, required fuel pump or filter capacity, etc. At WOT, you can figure about 1 gal. per hr. for every 10hp.

80 hp would equal 8 gal pr hr.
400 hp = 40 gal per hr.

Nothing very scientific about it, but it's always provided me with info that's "close enough".

 

[Chris1956]

Jet Boats are less efficient that prop-driven boats. Some say 30- 40% less efficient. So add that inefficiency to ahicks number to get between 10.4-11.2 G/hr at WOT.

 

[jkust]

I can only compare to my waverunner as it is my only experience with a jet drive. I can burn through 18.5 gallons of gas pretty easily in an hour if I'm really using it hard. They are beyond horrendous as to their fuel consumption. Your 80 hp is a third the hp of my engine but yours being a 2 stroke must make up for some of that gap. My neighbors know me as the guy standing at my jet ski lift constantly filling it up. If you have anything jet driven, get ready to spend some money on gas. Best money I spend all year.

 

[roscoe]

Jet Boats are less efficient that prop-driven boats. Some say 30- 40% less efficient. So add that inefficiency to ahicks number to get between 10.4-11.2 G/hr at WOT.

But the inefficiency come from the drive, not the engine.
Result is less distance covered, not more fuel used.

He is already running at WOT, fuel consumption will be 7 gal per hour if engine is running properly.

 

[flyingscott]

Which power head is in your boat Is it the 3 or 4 cylinder?