YOUR SAW PROBLEM
If your saw doesn't have any spark at all after getting hot, but runs good while cold, it can plain and simply be only one logical answer, infact I've run into this problem a few times myself!!! It's you coil... Possibly a loose spark-plug wire where it goes into your coil, just see if you can pull on it a little to see if it pops out... Check for ohms on your multi function volt meter and if its good should read about .001 resistance while touching part of coil with one of your wires and touching the other wire to the wire down inside you spark-plug cap... Now if this is the problem all you have to do is reglue it back down inside of your coil and to do this, just go to you local Auto Zone and go to the cement-glue section and get the type of cement that can be used on rubber, plastic, and metal "I think its one of the long drie kinds"... You'll need to clean all of the hardener off of you wire before applying it to the wire so it will stick like it needs to... After doing this and knowing what your resistance is suppost to be all you need to do is plug your wire back in and makesure its got a good connection by going by you resistance reading then take you mixed glue compound by putting it on a flat head screw driver and simply wipe it down in around your wire, all along forcing it down in around to makesure its down in there good... Make sure to hold it down in the coil during its anitial setup period and watch your meter all along to assure that it doesn't loose its connection... Let it drie over night atleast, maybe even a day before attempting to put it back on your saw... If this isn't the problem then its your coil itself and it will have to be replaced... The slightest looseness in your wire will cause this, because has good connection while cold, because of shrinkage and as it gets hot it expands and allows the wire to loose its connection... Well hope this wasn't too confusing and will help you solve your problem...
Greg