Congrats ! They are great little engines but the stud heads tend to break as the engines are quite old and threads very corroded. If that does happen, i find that a couple of days of regular soaking in WD 40, then attach 2 nuts to the remaining part of the thread, tighten one against the other, hold the top one in a spanner, then put a spanner on the bottom one and turn anti clockwise and hopefully it will unscrew. Use an extension on the spanners for extra leverage. Good luck.
