I have several YS 45 but I have one that sticks out......
This engine ran great for about 200 flights, then it begain to leak fuel back out of the carb......I replaced the dia, spring and plunger....runs super lean on top end, when idle back then to full throttle it runs super rich...Sooooo I went on a spending spree.....one peace at a time....needle valve, carb body, pump housing, gaskets, spray bar assembly a million different plugs and still same old thing.....I have runs this thing on 10 to 15% nitro with a nitro pipe.....HELP!