Yes, I did get my mower to work! The PTO lever had been slightly bent, and changing the blades somehow kept the pto from engaging. I used a very large screwdriver to brace against the lever (I got underneath, near where it attaches) then pushed hard against the handle toward the back of the mower. The goal is to bend the lever back because pushing it to engage the pto must cause it to bend forward over time. I still have to do this occasionally, but it causes the PTO to engage. I found this solution on the internet, and the person who figured it out eventually just replaced the lever.