I bought a Craftsman Professional Lawn and Chipper Vac to vacuum leaves off my 2 cares. It has a OHV I/C Briggs & Stratton engine. I mis-read the directions and overfilled it significantly with oil, probably twice as much as needed. I started it with this oil in it. Of course it blew out the muffler and smoked. I quickly turned it off and realize my dumb mistake. I drained all of the oil, all of the gas, and changed the spark plug and air filter. I refilled with fresh oil correct amount and fresh gas. Started right up, smoked for a few minutes, and worked great. Thoght I was clear. I used it for about an hour, dumpoed the load and turned it off to break for lunch. When returning from lunch, about an hour later, I am unable to start the engine. Following advice of many sites, I tested. It appears my fuel system is fine, but I do not have any spark at the plug wire. Did all that extra oil cause a problem? I don't understand why it ran flawlessly for an hour and now no spark. Is it time to take it in for repair? Thanks.