2 or 4 strokes

[alpamis34]

My question is about the marine engine type that I have been indecisive.Which type of engine would work better with a water jet propulsion? As I know the success is achieved when the high rpm engines are used,which one would you suggest me to use ? The 2 stroke is an old technology and more petrol consuming,isnt it? Cheers in advance

[gonzo]

Engine and pump have to be matched. RPM alone is not enough. Torque curve and HP are important too.

[Pericles]

Have a look here http://www.ultradynamics.com/section.../passenger.asp

Pericles

[stonebreaker]

Depends on whether weight is a factor. Two strokes develop way more power per pound of engine, because even though they're not quite as efficient as four strokes, they have twice as many power strokes at any given rpm as the four strokes do.