Called myself doing a good and careful cleaning job today on my original carb of my 1970 H model. Had a leak at petcock that I corrected. Got it running and adjusted to a smooth rpm, but after I revved it up a time or two, it would not return to idle. Had to turn off key. I redid everything 3x, but same results. What am I doing wrong. YouTube makes it look easy! LOL! Thx!