The DA50 uses a Walbro carb. On the carb there is a plate that covers the diaphram. On that plate there is a small hole. Sometimes that hole needs to have the air coming to it deflected to prevent pressurizing the diaphram. Never, never cover this hole up in a manner than can block it completely. Sometimes a line needs to run from the cover to a low pressure area in the fuse. All a matter of trial and error.