No one has touched this mower but me since it was new.  I've had no problems...just maintenance since March 2018.  I was on the mower, cutting grass and spraying ant hills for a hour or more and stopped to call someone.  That's how it was....the click of the PTO (clutch) changed.  It clicked when I turned the switch OFF....rather than on.  The seat switch is working.  I cranked the mower with blades rotating and moved it in my shop but stood up and it cut off.  The PTO switch is working but backwards.  The clutch has been a little louder than normal for 3 years...I bought a clutch 3 years ago.  I'll replace the suspect today and get back here.  If not it....I'll look at relay.  I also have a spare PTO switch....I buy stuff early inc. the belts I put on 2 months ago were purchased 5 years back.