A common DIY way to deal with that is to use a pair of locking jaw pliers to "pinch" the fuel hose closed. Use something under each jaw of the pliers where they touch the hose, to keep the serrations of the jaws from cutting into the hose. A few folds of an old cloth rag is usually enough to soften the jaws. While you are doing this, why don't you add an inline shutoff valve? If your fuel system is gravity fed (tank higher than carb) you need the benefit of being able to positively shut off the fuel when not using the machine.

Mownie: Thanks, just the information I needed.