85 hp fuel economy compared to 4cly I/O

[bretto]

When comparing an 85 Hp 2 stroke to a comparable not sure what Hp 4cylinder 4 stroke that would be on your basic 16' boat. How much better would the fuel economy be on the 4 stroke? No I dont want to be schooled on why a 2 stroke is better, just want to know roughly how much better economy I would get with a 4 stroke.
-brett

 

[WillyBWright]

Re: 85 hp fuel economy compared to 4cly I/O

Are we talking a sterndrive or a 4-stroke outboard? Regardless, it takes about as fuel to make 85Hp at full throttle no matter what kind of motor you have. Where conventional 2-strokes get wasteful is at lower RPMs. At idle as much as 30% goes straight out the exhaust without burning. At full throttle, they are quite efficient. Since the smallest I/O you are likely to find is a 120Hp, then it would logically use more fuel than an 85.