Ive had 3 engines I have worked on that I had at first set the carburetor very rich. It was so rich that it would barely start. They were puffing black smoke from the exhaust at first. After a couple of seconds it would slowly speed up and run pretty well. Next it would die very suddenly like the spark was grounded out. This has happened to a 8hp Troy Bilt tiller, a Tecumseh generator, and a Coleman generator. I cannot for the life of me figure out what would cause this. Once I leaned out the carb all ran just fine by the way, so nothing actually wrong with any of them. Does anyone here smarter than I am know what causes this?
