9.9 and 15hp parts are the same

[yamahasteve]

in looking up parts i found that all, not most, but all the parts between my 9.9msh and 15msh are identical part numbers. usually the crank, pistons, cylinders are same but carb or reed valves are different. in this case even the jets in the carbs are the same # and the carb itself. even the cylinder head has the same #. anyone know how the extra 5hp is made? is it in the gearing?

[almetelo]

What is the PID and S/N?

On some models is just the reed valve

[almetelo]

Please confirm PID and S/N to be sure this is correct for you/your motor

[yamahasteve]

pid 682k sn 1032232

[almetelo]

The data provided to you is correct for your motor

This is the reed valve for the 15HP

63W-13610-00-00 YAMAHA REED VALVE ASY

Do it at your own risk

[rodbolt17]

the 9.9 used a 2 reed box.
the 15 uses a 3 reed box.