Gas question

[krisnowicki]

I have a yamaha 200 I was out running for about 2 and half or three hours and used 20 gallons ... OUCH. Coupe of questions. 1 what is the best cruising rpm for gas "mileage"? What is to high of a cruising speed for an outboard? my wot is around 5800. is about 8 gallons an hour typical?

 

[tashasdaddy]

Re: Gas question

on a 200hp 8 gallons an hour is super. rule of thumb, is at WOT, you move the decimal in the horse power to the right one space, 200 hp 20 gallons per hour.

 

[dingbat]

Re: Gas question

Your fuel usage depends a lot on the hull. I have a 200Hp Rude and if I ran 2-3 hours at anything much above idle I'd use a lot more than that.

My cruise RPM is right around 4200-4500 rpm which yield right around 26 kts. per hour which get me roughly maybe 2 miles to the gallon so figure roughly 13-14 gallons an hour.

 

[steelespike]

Re: Gas question

Best cruising speed can be just above planing speed to about 2,000 rpm higher.
Trial and error or a GPH (gallons per hour meter)is the only way to determine the best rpm.Something like trim tabs will help plane easier and stay on plane at lower speed.

 

[jtexas]

Re: Gas question

My experience (without any fancy measuring equipment), general rule, fuel burn at 3/4 throttle is about half of WOT. I think for a given throttle setting on a given engine, pounds of fuel per hour is pretty much independent of most variables, whereas miles per gallon depends on things like hull design, weight & balance, wind & current, temperature, gear ratio, prop design, equipment condition, and density of the glitter in the gelcoat.