mannyzgti

I purchased a 96 sea doo sportster about two weeks ago. I went for a ride with the seller with no problems. A few days later I took it to the water. It starts up fine but after about 15 min it just cuts off. After removing the key several times it will start. Then it will continue to cut off after 5 min or less. Has anyone had this problem before? I'm new to the boat world. This is my first boat and I would really appreciate any help.