My OS 40LA didn't start after a winter in storage. I hadn't been taking care of it while in storage so a friend suggested I disassemble it completely, remove any rubber parts and soak/clean it in methylated spirits. However one of the carburetor screws was so tightly fit that I didn't have a chance getting it out. It ended up ruined. Without the proper equipment to drill it out I decided to reassemble the engine. However I can't get it satisfactory. The piston and the sleeve around it seems to fit badly. I can get them both in, but the piston won't turn smoothly. In fact, it won't turn more than in the bottom half. Any idea why the piston doesn't fit properly? Is it supposed to be aligned in a special direction?

As for the engine not starting; it did run for about 2-3 seconds, but it seems to not be able to draw fuel. Turning the prop manually didn't draw fuel into the carburetor, only if I blew into the pressure hose (normally connected to the silencer.) I might be wrong, but is there anything that may cause the engine not to draw fuel?