I replaced the fuel filter twice.
Checking the venturi "O" ring and sealing on the N/V assy. is next on the list, thanks for your reminder.
I will also try muffler pressure. I have never run an engine on pressure, but this might be the ticket for the LA engine.
One thing I did notice since installing the ST N/V assy. is that I get good 2-4-2 (more 2 than 4) at 10,300 RPM, with the needle only 1 turn out from being closed, but it will not start again unless I turn it 2 turns open and then close it down to about 1 turn to get good setting for flying. Seems like only 1 turn open is very unusual.
Jerry