That's a good question and to be honest I really dont know. I rebuilt the carb and the only thing that looked gummed up was a(the) jet. The inner bottom of the carb was a little dirty or varnished but not bad I didnt think. At 1st I thought it was just oil that was too full. Then it occurred to me that it smelled too much like gas but didn't appear to have that faint cloudy look that I associate with gas mixed with oil and it wasn't watery. Was busy right after getting it so the oil issue wasnt discovered until hrs later when I went to take it for a spin. Like everything new or new to me anyway I always check the oil before running an engine. That's when I discovered what eventually ended up being roughly a quart too much oil in the engine and the beginning of the cluster f*** I'm in right now.