I have a Briggs and Stratton 31c707 0154-E1 engine on and MTD Yard Man mower.
Total use about 30 hours. Age 1 year 1 month. Problem: engine threw a rod, both rods. Bearing cup is seared. Repair shop says I must have ran the engine low of oil, and will not honor the warranty. I checked the oil myself before it blew up and there was fresh oil in the crankcase. There was still oil in the crankcase after it blew. This mower has a safety shut off switch in the seat. Everytime you shift your weight, the engine cuts off then when your weight settles in the seat the engine restarts and you get a loud expolsion in the exhaust system. I believe that this explosion after 50 or 60 times is what caused the engine to throw a rod. The mechanic that does the warranty work says that the exhaust explosions could never cause the engine to throw a rod, I think it did. I would like an expert opinion from an unbiased expert. Thanks