Probably is the fuel pump. I have a Winnie and F150. The F150 pump went and did the same thing. The pump on the F150 is in the tank and is liquid cooled. When it is running, all is good, but when you stop the pump, it basically siezes up and then has difficulty getting turning again. What I did until I got it fixed was took a small 2x4 and hit the side of the fuel tank really hard. This is enough to jolt the pump a bit and then it would restart. Not sure on the Winnie where the pump is, but on the F150 it is near the drivers side towards the front of the tank. Some times it took a whack or two to get it to start, but give it hit. Then try the key again. If that works, then you need a new fuel pump!