50 HP vs. 60 HP

I have a '06 50 hp 4-stroke EFI Yamaha. I am not at all unhappy with engine. So smooth and terrific mileage. But I see that the 60 hp version of this motor has the exact bore/stroke/compression ratio as mine. What did Yamaha do to increase the power? And can I do the same to mine? I'm pushing around a 20' pontoon and don't ever expect a hot rod, but this afternoon I was caught out on the lake in a fast developing thunder storm and wished that I could return much quicker than I did. Five miles at about 12 mph seems like a long time!

[spartacus]

I have a '06 50 hp 4-stroke EFI Yamaha. I am not at all unhappy with engine. So smooth and terrific mileage. But I see that the 60 hp version of this motor has the exact bore/stroke/compression ratio as mine. What did Yamaha do to increase the power? And can I do the same to mine? I'm pushing around a 20' pontoon and don't ever expect a hot rod, but this afternoon I was caught out on the lake in a fast developing thunder storm and wished that I could return much quicker than I did. Five miles at about 12 mph seems like a long time!

I suspect it's increased airflow and fuel injection settings, together with larger exhaust manifold. Looked at similar issue with upgrading 2-stroke 40hp to 50hp which uses the same block, etc.