started using a bx1500d with the 54" mower deck. it seems to have no power and bogs down with simple lawn mowing. it has fresh oil and air filter. have not changed the fuel filter and i am unsure of previous maintenance on this machine. i have a bx2200 and it just powers thru grass of any height with somewhat dull blades. the 1500 has new blades. hydraulic fluid is full and clear with a fresh filter on. any suggestions?