Over the years I have learned the hard way how to remove screws & bolts that are frozen. Using the techniques below I seldom need any specialty tools for removing screw, bolts & nuts.
Here are some ideas that might help you:
Removing the Small Screws on the Choke, or Throttle Shaft
Take your time removing these screws. It will pay off big time. These screws are usually mushroomed on the threaded end. Using a dremmel tool, grind the threaded end flush with the shaft. Using a screw driver that fits the screw head well, twist the screw counter-clockwise. It is sometimes a good idea to turn the screw back in, then out again. This helps flush out rust particles. Don’t turn too hard, or the screw will break.
Not coming out? Put a block of some kind on the threaded end to prevent the shaft from bending, then hit the screwdriver with a hammer while you try to turn the screw. This will sometimes break the screw loose.
Still not coming out? Using a butane torch heat up the area around the outside of the screw. Don’t apply too much pressure, or you risk bending the shaft.
Did you break the screw? You will have to drill & tap. Using a drill bit (and a good one), just shy of the screw diameter, drill out the screw. If you do this carefully you will be able to remove the screw without damaging the threads. The trick here is to have a good set of small drill bits.
After inserting the new screws, you can mushroom the end, or as I do use thread locker.
The best way to un stick frozen shafts is to heat the area outside of the shaft and tapping on the end of the shaft. The shaft will almost always come loose. If it doesn’t then it is most likely beyond repair.
Frozen Screws, Bolts or Nuts
When a screw is damaged to where a screw driver won’t hold, use a drift punch and hit it a few times with a hammer. This will cause the screw slot to shrink hopefully enough to allow the screwdriver to work. The banging will often times jar the screw.
For bolts use the same drift punch technique to see if the bolt comes loose. Avoid using 12 point sockets. A 6 point will give you a better grip. When a bolt start to loosen, then tightens up, stop. Try moving the bolt back and forth to help loosen it up.
Still frozen? Apply heat around the outside of the screw, bolt, or nut.
Always use good tools and the correct tool on nuts & bolts. That does not include a cresent wrench.
Nut or Bolt Has a Stripped Head
Use a flat file to file the flat parts and remove the mushroom edges. From there try a smaller socket or wrench. Sometimes moving from a US wrench to a metric wrench will do the trick, otherwise a vise grip will be in order. Again applying heat will probably help the nut, or bolt move easier.