I have an MTD Snowthrower that I acquired from a neighber last fall. It has an 8 HP Tecumseh engine on it. After running the engine for about 5 to 8 minutes the muffler and bolts that hold it on glow orange. It also occasionally spits out sparks. I had a local dealer tell me that this is not uncommon for an MTD product. I've never had this happen on any small engine I've owned, but I've always bought a higher end product - this one was free. Is this common or not?

Thanks