I like you Al , but how about you take the time , and a little money , and build and test a clone engine . Im not trying to start anything , just think that if someone wants to add to a conversation , they should be versed in the conversation . Just sayin !With 2 cycles, when the carb is tuned to racing conditions, none of them will idle. Depending on your air density, you didn't say where you're at, it could just be the engine is running rich because it's not getting enough air. I had a brand-new 1963 Plymouth 383, I went to Tahoe, 4000 feet, that 383 was spiting black smoke everywhere I drove.