I am surely gratedul for all the help I can get. I get the best RPM with the HSN ~ 3/4 out, and the LSN ~ 4 1/8 out.
I set the HSN by starting at 1 1/2 out as per manual and slowly leaning while checking speed with a tach. The tach btw works, as it gives be 3600 when I point it to a flurescent light in the shop.
The regulator screw is slightly out, but I did not see much difference with it flush or even a bit in.

The guy who sold it to me said that it had a new ring in it, new diaphragm, bearings, gasket set and needle valve assembly.

I will try Four Stroker test to make sure the regulator closes as it is supposed to. Though last time I ran it, I did pull the line from the regulator to the carb with the tank still pressurized, and I did not see any fuel coming out.
I may also be able to jury rig a pressure gauge to the tank, to make sure I get enough pressure in the tank. Not sure though, depends what we have in the lab...

Alberto