My lil red express hasn't ran in about 2 years, I went out got fresh gas, it cranks and fires when I hold it in the start position, but as soon as I turn the key back to the run position, it shuts off. I checked the timing, checked all the terminals at the ignition switch with key in run and off position, I have a full msd ignition system on it so it's not anything like a ballast resistor or anything. I'm thinking maybe starter relay? Anyone have any thoughts? Thanks for any help