Don't get rid of that motor yet, If you are mechanical inclined; you should tear down that motor and rebuild it. Take it apart and soak it in denatured alchohol. If it has bearings soak those in WD-40 or similar, once you start rebuilding the engine you can use either a few quick shots of WD-40 or a few drops of motor oil to lube the sleeve and piston and crankshaft etc... I have never had to rebuild a airplane engine, but I rebuild my car engines about once a month sometimes twice a month. Also when you rebuid, you can put all the needles back to their rich starting setting and tune from there. You want to tune starting rich and working to lean, once you have the engine at optimum rpm you richin the needle a 1/8 to 1/4.