ok, i have a Briggs 12J802-1960-E1 mower motor thats surging when i turn the speed up. when i put the speed lever up to rabbit it surges a little bit. now the motor has been sitting for about 4 years outside under an eve, but even after that once i put fuel in it, it started on the 4th pull. then died, i changed the plug and it fired right up blowing ALOT of oil smoke out which went away after i let it idle for about 20 minutes. well it has been tipped and turned every which way and upside down during those years and just today it tipped upside down twice when i was dropping it onto a spare deck. so why is it surging only when turn the speed up and what can i do to fix it? when its under load mowing it doesnt seem to do it, or does it to a much lesser extent. i really like this motor, it runs like a champ and powers through it all. also can someone tell me what HP this motor is? the decorative plastic bits on it are long gone, thats what had the sticker telling that. i know its 190CC and cast iron sleeved, its an I/C motor.