MacGregorSailors.com

So given that the 2.5 hp does 1 lb./hr of runtime, and the similar Tohatsu 2.5 hp gets 0.4gph

Something is fishy in Denmark...

0.4 gph and 6 pounds per gallon means 2.4 pounds per hour for the gas version

There is no way the propane version is 2.4x more efficient, especially since propane has only 80% of the fuel value of gasoline.....

Catigale wrote:

So given that the 2.5 hp does 1 lb./hr of runtime, and the similar Tohatsu 2.5 hp gets 0.4gph

Something is fishy in Denmark...

0.4 gph and 6 pounds per gallon means 2.4 pounds per hour for the gas version

There is no way the propane version is 2.4x more efficient, especially since propane has only 80% of the fuel value of gasoline.....

Something is wrong with Tohatsu's published fuel consumption for their 2.5hp. It uses nearly as much fuel to make half the hp as their 5hp. This accounts for most of the math issue you point out.

According to Tohatsu's site, the 2.5 4-stroke burns .24 gal/hr, and the 5 hp 4-stroke burns .5 gal/hr. http://www.tohatsu.com/tech_info/fuel_consumpt.html

Okay, that puts the Tohatsu right at about 1 lb. per hour, which is in line with the propane.