Kubota Engine H.P. Boost!

[BWH]

I have a Kubota engine question, I have a 21 H.P. gas engine (WG752-E2S) on a 2001 721 Grasshopper. I have noticed in my owner痴 manual that the specifications for the Kubota in the 21 H.P. 721 Grasshopper (WG752-E2S) & the 25 H.P. 725 Grasshopper (WG752-E2) both 45.2 cu. In. are identical in every detail. I have to believe that it is in the carburetion where it is making the extra H.P.? I noticed in the Kubota engine manual that there are jet kits for higher altitudes would it be possible that it is just a re-jetting kit for the additional power? I do know firsthand that Briggs & Stratton did this exact thing in the early 90痴 with the 12.5 V-Twin and the 14 H.P. V-Twin they too were identical with the exception of the carburetor. I purchased a new carburetor for a 14 H.P. and put on my 12.5 H.P. the increased power was very noticeable and worth every penny. With all that said are there any Kubota people out there that can shed light on this idea?

 

[AmericanTurf]

I "think" the jet kit is for oxygen. Not to sure about the hp.

 

[BWH]

Thanks,

That would stand to reason being an elevation or thin air thing. It does make me lean towards the idea that a totally physically different carburetor would be more of what Kubota is doing to achieve additional H.P. utilizing the same engine.