I bought a toro zmaster 60 in deck with a 25hp aircooled motor used. appx-750hrs. ive only ran one season on it. and ive noticed it seems to be running like its not at full power. i have used zmaster 26hp liquid cooled ones alot. and the power is highly noticeable. and my 25hp mower when turning to the right, really labors. and the top speed is alot slower than the 26hp. ive check the hydro pumps. and changed the hydro fluid. now i need help figuring out are the 25 hp's have a major power difference from factory? or i have no clue what would be making the power difference?