Here is one for you engine tinkerers. I tore up an old echo CS-51-evlp today. I had little hope for it before I started, it was seized. Normally that is because some hammerhead ran straight gas. I expected the jug and piston to be trash. I only wanted the crank anyway. I let it sit with Kroil in the jug for a week before I started. Expecting the worst I got into it today. It was stuck beacause the "hammerhead" found a way to get a bunch of water in it. The main bearings are shot but, the crank and piston bearing are fine. The inside of the case was corroded but not in the bearing seats or anywhere else that matters. The jug an piston are shiny and good.

Unfortunately, the rings are stuck in the grooves. Is there a clever way to free up the rings? I was thinking of using a jewlery sonicator and Kroil. Maybe if I vibrate them enough in hot Kroil the rust will work it's way out and the rings will pop free by their own tension?