Thirsty Yamaha

Clint KY · Sep 27, 2014

A friend recently got a 20’ Crestliner with a 70 HP Yamaha 2 Stroke. We spent the day on the river and that motor sucked 6 gallons of fuel in less than 2 hours running.

1. – Is this normal for this motor?
2. – If so is there anything that can be done to make it less thirsty?

lckstckn2smknbrls · Sep 27, 2014

I don't know if this formula works for higher HP motors but a 10hp motor will use about 1 gallon an hour at WOT, a 25hp motor will use about 2.5 gallons an hour at WOT.
A 70hp motor might use 7 gallons an hour a WOT.

Djknyork · Sep 27, 2014

Sounds about right to me. My 40 Evinrude 2 stroke would prolly burn that much in 2 hours of running at WOT. I've found that running at 3/4 or 1/2 throttle makes a huge difference in consumption

Boat2fast · Sep 27, 2014

On a 6gal tank, a 150hp Mariner/16ft Checkmate gives about 1 hour of heated playtime before getting towed home...

marshman · Sep 28, 2014

I wouldn't have thought a 6 gallon tank would hold enough to crank a 150
Mariner!! Haha..

Tallpine · Sep 28, 2014

A 70hp motor would be working pretty hard on a 20 footer if you are pushing it. I get a couple fishing trips on 6 gallons with my 20ft pontoon and 40hp Mariner and I'm puttin around on 10 mph lakes. I have never checked mileage or time running but I sure wouldn't head out on a 2 hour trip with just a 6 gallon tank if I was going to be running hard the whole time.

turbotodd · Sep 29, 2014

https://yamahaoutboards.com/sites/default/files/bulletins/bulletin_2stroke_hpmidport_al_sa6d87.tmp.pdf

Everything I've referenced shows around 7.2-7.5 GPH at wide open throttle, so you're probably not too far off. BTW, most of the F70 (4 stroke 70 hp) motors aren't too far behind at around 6 GPH. But it IS, nonetheless, a sweet motor.

Thirsty Yamaha

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