Breaking in new top end, running oil reservoir low to change brands, and running premix for break in. Ran 3/4 tank of gas through, filled up with fresh gas and didn't get more than 1/2 mile and engine shut down no spark. Oil in reservoir was right at the riser spout in the bottom of the tank, and so thought there might be a shut of switch as I have absolutly no spark. There was oil still in bottom of tank about an inch or so. Wondering what plan of action to take, I don't think motor is burnt as it turns over like normal, but have no spark. Any suggestions?????