3 - 53 rack info?

This is the governor. It was all clean before I ran it with the valve cover off. I still need some help please!

The old injectors were set at about 1.540, using a dial caliper. I was reluctant to make that big of a change but found other similar settings on line to Simmons 1.480 and went with that. I even had that gauge. Installed an electric fuel pump before the primary filter and let it run while I put all the tools away. Took that pump out of the system. and cranked it at about 1/2 throttle. It came to life shortly and I kept it down at a lower speed " no tach " and checked all the fuel lines for leaks and worked it on up.
Brought it back down and it shuts off with the throttle as it is pulled back. Push the throttle back up and it fired right up.

It runs great a the top 85% of throttle but if left running at lower speeds it starts to act like it is running out of fuel. If down around 750? RPM it will shut down. No one can tell me if this is a new thing or prexhisting condition. Ran it at higher speeds and shut it off. Hours later it was hard to start. Will go back with clear fuel lines and gauges.
Did not take the top off the governor. The gasket would have broken and I did not have thin paper. Backed the buffer screw out. Tied the shut down full open. Throttle did not seem to make much difference 1/2 maybe. Ran the rack. Did not find an idle screw like I expected. It is probably the screw on the back of that long housing but I did not want to be a knob dicker.
Any good advise and or copies for this unit out of the shop manual appreciated.

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