If my scott s1642 will only runs when I hook jumper cables from my car and turns off as soon as I remove them do I need a starter/alternator or are there other options

Are you jumping the battery or the starter? Position of the start switch?

OK, I get the feeling that you have the jumper cables across the battery and the mower dies when they are removed. I also gather that you have to have the cables connected to start the mower.

Battery can be tested before a new one is purchased. Battery likely culpret.