Jennifer, I had a similar problem with my lawnmower recently ( Honda Izzy), I too tried everything, new filter, cleaned out the fuel tank, cleaned out the carb. As a last resort i re gapped the spark plug,It worked. So i bought a new plug and the mower runs like new. Hope it works for you. please let me know on wembley666@yahoo.com Good Luck
Jim D, September 2008