Did you check all the safety switches? On my TC26DA I had a problem and found one of the sensors (forget which one, but think for PTO) wasn't being fully engaged and a small adjustment there fixed iit. Whenever it works for a solenoid jump and not from the seat I suspect one of them. The PTO one is particularly finicky because it's designed to be run when the seat isn't occupied, but not allow a start when it's not fully in the "not engaged" mode. The TC26 had a button, I think that worked off the lever. My Workmaster 40 is a different one from yours and I don't have a clue how even mine works yet..