I have a Toro Zmaster... Model number 74176. Serial number 210000478. Over the last couple of weeks, I have had an issue with the engine cutting out while I am mowing. Doesnt matter if the blades are on or not. And it would only happen a few times in a day and for only a few seconds...then it would run fine. I replaced the fuel filter and the fuel pump. This didnt fix the problem. I opened it up today to look around. Cleaned off the fins on the cylinder heads. Then I fired it up with the cover off and noticed ALOT of sparks coming from the left side rocker case. It was also giving off a weird smell. Cant really describe it...not a burning wire or burning oil smell....something in between. I shut it off because I really didnt want a fire. Can anyone help me figure this one out???