How many of you use synthetic oil in the motors of your mowers? I have personaly witnessed a Buick with a V8 have over 300,000 miles on it being torn down for a freshen up rebuild. The motor got Mobile 1 every 3,000 miles and when it was torn down it was so clean you could eat off it. There was still the original factory cross hatches in the bore's and no wear ridges at the top of each cylinder. Also the bearings looked brand new and not worn down. The guy figured it was time to rebuild it but it really didnt need it at all. Now if it works that well in a car engine I dont see why it wouldnt work wonders in a mower engine. I know mowers operate in a completely different climate with all the dirt and dust but if a person keeps there air and fuel filters clean or changed I personaly dont see how hardly any dirt could penetrate and contaminate the motor oil. I know its a bad bad idea to switch an older higher mileage or higher hour engine over to synthetic because they can develop oil leaks. I am thinking about switching our Kawi over because it only has less than 400 hours on it.