[spareparts]

horsepower readings alone will get you into trouble, horsepower is the timed application of torque( hp=(torqueXrpm)/5250) you have to know what the rpm the hp is rated at. I've seen a 50 trawler with a single 125 hp engine make 7 knots, it would take two 5.7's to do that in this boat. Saw an model airplane engine that would make 5 hp( at something like 15,000 rpm), but I bet it wouldn't push my lawnmotor as well as my 5hp Briggs. Torque alone won't tell you much either, think of a torque wrench, you're applying torque, but you're not going anywhere. I've started to pay attention to Kw ratings(used on modern engines), I haven't made my self familure enough with them to know what I'm looking at.