I use 2 cycle oil in the meter since it readily burns off if sucked in. A small ball valve at the bottom of the loop allows control so you don't suck anything in. Once hooked up and bike is running slowly open the ball valve if it starts to get sucked too far you can close it again and adjust and try again until you can leave it open to adjust.

I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!