what is Fuel mpg difference between 150 & 115 hp 2sroke??

[Iratherbefishing]

I am repowering my 21 ft seacat boat.

 

[Mischief Managed]

Re: what is Fuel mpg difference between 150 & 115 hp 2sroke??

If both are making 115 HP, the 150 will have an edge in MPG. Two strokes get really inefficient at WOT, so at cruising speeds, you'd probably do slightly better with the 150. At WOT, the 150 will use obviously more gas, but you'll be going faster so the MPG will likely be only slightly worse than the 115 at WOT, simply because that's how boats are.

 

[Silvertip]

Re: what is Fuel mpg difference between 150 & 115 hp 2sroke??

The basic rule of thumb is 10% of the HP rating. So 11.5 gallons/hour at WOT for the 115, and 15 gallons/hour on the 150. Unless you have a fuel flow monitor or have access to some performance data, anything less than wide open throttle is just a guess. Visit Yamahas web site and view their performance tests. You can pick nearly any boat and chances are they have tested it with a variety of engines.

 

[Chris1956]

Re: what is Fuel mpg difference between 150 & 115 hp 2sroke??

Repower that boat with 75% of max HP. I would think the 250HP motor will be closest to this figure. The 150HP motor is likly and V6. The 115HP motors are either IL4 (Merc) or V4 (OMC).

 

[pmillar]

Re: what is Fuel mpg difference between 150 & 115 hp 2sroke??

That's a very timely and topical question for me too since I am looking to repower with something in the 115 to 150 range. In fact, I could sell you my 115 FastStrike that gets outrageous mileage... it burns no gas at all. Of course that might have something to do with the holed piston and trashed powerhead