Purchased riding mower in 2015. 42" Pony with 420cc ohv engine. All was good for 4 years then it quit running. Shop replaced one of the lifters that had cracked and bent. Less than a month later the other cracked and bent. Shop mechanic (in business over 20 years) said the Chinese made Powermore engines are made of inferior steel. Last week a loud bang and the motor locked up. The cause was the flywheel magnet had impacted the spark coil, stopping the flywheel dead, shearing the flywheel key. On further inspection the crankshaft was also dug out and rounded. Like it was softer steel than the flywheel key. A new key has a lot of play, so much so that when I started it up again, it started to run, backfired and died. The new key had not held as the key slot in the crankshaft was now to hollowed out to support it. My next riding mower will be American made.