I am going to pick this 10525 up tomorrow. Looks pretty much perfect. I do have another motor just in case. Owner has been using it all season. Last week he said he can't pull the cord or spin the blade this week. He thinks it has a seized motor but says he always uses 32:1 mix and hasn't straight gassed it. Am I making a mistake assuming he is telling the truth? What else would cause the motor to lock both at the starter and blade? Thanks.