I have an early 90's 12.5 HP stx38 and it wont take me up small semi steep hills its a non hydro and the tires aren't slipping when it has traction the motor bogs down any ideas
That's a 'belt' drive mower...
Remove the belts and check all the pulleys and idlers, see that everything spins freely without binding or dragging... pay particular attention to bearings and bushings as they may seem ok until you pull things at an angle ... :smile:KennyV