Anyone, My father has a Husqvarna Rider 155 that will start and run fine but when I turn it off, it may start up and may not. I checked the battery for voltage and it is around 13-volts which seems fine. I've cleaned contacts and checked the 15 amp fuse. I told him to have the battery checked under a load and then if that does not work, then it could be the starter. Any ideas? Thanks, R.