I have a change to buy a Honda HS621 single stage snow blower at a real good price. It starts up and runs good engine-wise; however, when the blower enters snow to blow it off the cement it revs down and then it dies according to the owner who says its 8 to 9 years old and has been used commercially too. What would cause this to happen as I want to know how much the repair would be or if it is just something needing adjustment. Could it be the governor needing adjustment, a belt, pulley, gearbox, or something else? Thanks.