I've had the same problem a few times with a 35 year old Poulan Micro XXV. Sometimes, but not always, it won't start when hot. But if I let it cool off, it will start again.
As you found out, there isn't any spark. That isn't a compression related problem. An engine that has just been shut off will have HIGHER compression than when you started it cold because the cylinder is coated with oil. So I don't think compression is your hot-start problem. Lack of spark when hot indicates a coil-related problem.
I have a bigger Husqvarna saw, too, so when the Poulan gets cranky, I just pick up the Husky and work with it until the Poulan cools down. That beats actually fixing the Poulan because I don't know if parts are even available for it anymore.
Word to the wise: Don't loan out anything you're not willing to give away. Because sometimes that is exactly what you're doing.