Small Engines (Lawn Mowers, etc.): muffler, broken studs, pipe nipple

Question
I was given a JD1400 a couple years ago, and my friend said it wouldnt run. I pulled it out the other day and found the gas lines cut and muffler bolts broke off inside the head. I could try drilling them out and tapping, but the thing ran great after replacing the gas lines. I would like any input on the tidious removal of broken screws.b1145

Answer
 Hello Tommy:

 Check the Inside of the Exhaust Port and see if it is Threaded for a 1" pipe Nipple. Most Engines are. If not, then Center Punch the Broken Studs. Start and Run the Engine until Hot. Using a Pre-selected Reverse Cut Bit; Drill out the Old Studs. I suggest getting the Engine Exhaust Port Tapped for 1" pipe if it isnt already. Hope this Helps.

 Good Luck

 Respectfully

 John