This has probably been posted before, but I thought Id give it another try. Im curious what everyone uses in their mowers. Ive always used Pennzoil 10W30 just because that is what my dealer puts in all his mowers and Ive always thought it best to keep using the same brand name. Ive tried full synthetic before but I thought the engine ran "different" so I went back to regular, but I would like to use full synthetic for its benefits. Someone once told me that if you have to add engine oil, you have to add the same brand name oil, not just the same weight!, I always thought as long as it was the same weight, the brand name didnt matter, but I was way wrong!