Ron, I had sticky valves (my motor has been drowned a few times prior to my ownership) and I was able to free them up with MMO squirted into the cylinders, similar to Tom's approach. If you can get it to free up with a penetrating oil, you might be able to lube the guides with MMO. For about 3 or 4 months, I squirted MMO in religiously after every use and then it it sit with MMO in between runs & it eventually popped free. Mine was never stuck wide open to the point I was losing an entire cylinder though.
YMMV
