Always check your blade spindles and grease them every so many hours per manual. Pto clutches are a good place to go next. Electric things fail. I bought a husqvarna z4824 that had been sitting outside non running for about 3 years in rain and whatever the good Lord threw at it. Needless to say I started tearing down everything cleaning all contacts and changing solenoids and cleaned carb but wound up changing it. Have changed fuel lines all way to carb. Vacuum tube for fuel pump was corroded changed it. Spark plugs, wires, filters. Changed pto switch and ignition switch. Oh and new battery. Needless to say after hundred of dollars and hours of sweat and alot of words later still dies out when engaging blades unless I let it warm all the way up then engage blades at half throttle by shimmying the pto switch off and on a few times real quick until it runs. Also wont start without ether. I have also reset valve clearances with feeler gauge twice. Bout to cut my losses cause I have to cut my lawn.