I've put several engines back in service over the last year and a half. Parts that would move, even the slightest bit, were loosened up in no time with a bit of alcohol. When I encountered parts that were completely stuck, such as a couple carbs, I put them in the oven at about 350 for 10 minutes or so. The heat loosened up the gummed castor enough that I could move the part so I poured in some alcohol and move them. The alcohol quickly cleared out the gummed castor. One other thing to do is to remove the needle and make sure the spray bar is clear of gummed castor. Once the alcohol was running clear, meaning I got out all the gunk, I put the engine in the oven for about 10 minutes to evaporate any remaining alcohol. Then I removed the engine, lubed it with machine oil and put it in a plane to fly. Every one has worked great.