Comparison Question
 

i have a 1997 aluminum Xpress, the boat tag says it is rated for a 60hp, everywhere i look online it shows that a 60hp and a 70hp two stroke yamaha have the same weight, why would the boat only be rated for a 60 when they are basically the same motor, could it be that the extra 10hp is putting that much more torque on the transom??? i don't understand, can some one explain this too me, i need to upgrade my motor but if i can i will put the most horsepower i can

I don't know the answer to your question but I will add that outboards today don't weigh the same as they did in 97' either.

yes
 

i have noticed that as well, but still the newer model yamaha 2strokes(even though they are no longer being made) the 60 and 70 weigh the same, and there is less than 10 pounds difference between the 4 stroke models

Not all manufacturers use the same block for the 60 and 70hp motors. The first that comes to mind is Mercury. Their 60 and 75hp motors were 2 totally different animals.There is a formula, dictated by the Coast Guard, used to determine max hp for a give boat. If that formula comes out to 60hp, that is what it is rated for.

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70hp block is completly different from the 75hp block also

How would i go about checking see what my boat is rated for in today's standards

Email the manufacture with your questions. I'm sure they will tell you straight up.