After riding for a few hours on and off. After coming to the top of a hill and shutting it off and letting it sit for 10 minutes or it would start back up. Had spark but no fuel, put some fuel in the cylinders and it fired til it burnt out. After trying a few times we gave up and decided to tow it out. We got a little ways and got stuck. I decided to give it another try and it started right up, and drove it back for half hour or so and no problems. Even shut it off and started it a few times. So is it the pump or the voltage regulator. Sled doesn't have handlebars earners or a headlight if that matters.