In the ground test, I opened up the high to 2 turns out from 1.5. For low needle, about 1/8 either way from 1.5.

Visually confirmed that the throttle plate can reach fully open position.

Normally I do not run the engine dry at the end of day. Wonder if the oil starts to deposit in the passages inside the carb. This could restrict the flow of the fuel and caused lean run. The plane is stored in garage and the temperature there can hit 100 in summer.