I have a EB630 and one of the muffler bolts broke off and I have tried to get it out with vise grips turning the bolt. It has turned some, but won't loosen. I think the bolt is somehow cross threaded. Any way this can be repaired? could I cut it at crancase and then drillit out? Would there be enough metal left in the head to put a helicoil? Are there other suggestions? I have ordered another blower, but this one still runs fine if I can get the muffler attached again somehow. THe unit is about 4 years old, so i thought it wouldn't be worth putting a new head on it.