Fuel burn for a 9.9hp Yamaha outboard

[oneilseamark]

Anyone have an idea of what the hourly fuel burn is on a 9.9 hp Yamaha four stroke pushing a 4k lb sailboat ?

[bruce smith]

For 2 cycles, the rate is roughly one gal per hour per ten hp., wot.
I would guess that you would not be running wide open throttle with a 4 cycle , and of course they use less fuel.
The vessel itself has very little to do with fuel use. It would use about the same, per hour, on a planing skiff going 20 or a barge going 2.
So, I think you will easily get 2 hpg,maybe a tad more, at about half throttle

[Ian R]

I average 1.3 liters per hour @ 3000 to 3500 rpm doing 5 to 5.5 knots in no wind, consumption goes to about 3.5 liters/hour WOT doing 6.7 knots. I changed to a 7 inch pitch prop from 9.25 inch ,no change in fuel consumption but gained .3 of a knot at WOT. I assume you have a high thrust motor ?

[oneilseamark]

I assume it's high thrust. It's new to the owner. Thanks for the great info!!

[HueyHuey]

On my old catamaran I ran 2 of these motors and consumed approx 5.5 litres per hour on both motors at full throttle. I had the high thrust props. Obviously significantly less when run at less revs.

[Ian R]

The yamaha service manual quotes maximum fuel consumption of 3.9 liters/hour @ 6000 rpm for the 212 cc motors.

[cjones]

Seems like numbers are consistent. I have one on a 27' Oday and running at about half throttle results in a burn rate of .5 gallons per hour. Wish I had a better way to track RPM but have no tachometer.

[neilpride]

I own a 9.9 4 stroke for 4 years before i get the engine stoled in St Lucia , i can give you 2 good advices based in this engine, 1. Try to fresh water flush this engine often if you can , 2. Use the Factory aproved or a equivalent oil and change it at the regular intervals.

Flushing the engine save you lots of cronic water flow problems and expensive repair bills , mine get some internal corrosion at the oil pan case and the water flow is restricted giving us a terrible nightmare to found the problem.

In other words is a great engine , and can last forever if you take care of this 2 points.

No idea about the fuel burn, but i remember the gas at the tank last for a long while,
my actual 15 enduro 2 stroke suck the whole tank in 2 days !!
Cheers.

[Factor]

Got two, life time average so far is about 1.15 ltres per hour per motor. Can use up to 2.2 litres per hour if pushing hard.