My very old OS20 has the throttle gummed up and is stuck at around full throttle after many years of sitting. I managed to get it running today, hoping the heat generated might help free things up but no joy, so am after any useful ideas. I have a few other engines that will be much the same when I go to resurrect them! On the positive side the old 80/20 castor fuel has preserved it well from what I could see when I removed it from the model for a clean up and external degunge. My best guess is to soak the carb in new fuel (for a few days?), unless anybody can come up with a better solution.
Thanks.