Yamaha 20 HP autolube upgrade to 25HP

[raczekp1]

I have 20 hp yamaha 2 stroke autolube with twin carbs.
i have seen the sam motor but 25 hp .any imputs how tu increase power?

 

[boscoe]

Using the Yamaha parts catalogs, compare the component differences between your 20 HP model and the most similar (by type and year) 25 HP model. Remove any parts that are peculiar to your model (not used on the 25 HP). Buy and install any parts that are peculiar to the 25 HP model (not used on your 20 HP model. You will now have the equivalent power output of the 25 HP motor.