UPDATE

OK guys...I followed the suggestions by some of you and here are the results:

1. OIL. I discarded my old fuel and went all synthetic Amsoil at 1:80 ratio (Amsoil recommends anywhere from 1:80 to 1:100), Brison's recommendation is 1:80.
Results are splendid. My LS needle is at 1 3/4 & HS 1 turn. Engine runs perfect, transition is great.

2. Throttle cut-off. I had to remove the idle stop screw from the carb. There are 2 screws to adjust idle. One is the spring loaded screw to adjust the low end idle and the other is the actual throttle stop which is on the carb. I removed both. Result is a reliable idle at 1500 RPM and I can kill the engine from my throttle trim.

Thanks all for your help.