Float bowl level, Using bowl level gauge Options

[scrz914]

I bought the float bowl gauge from partsklassik to double check my bench settings on the float and needle valve. I was surprised to see the level rise to the top. I shut the pump off before it overflowed. In reading the instructions I noticed it said to do the check while running the engine. I only ran the pump. Is there any reason to believe the levels would be different between running the engine as opposed to just running the pump? Also, is it possible that the needle valve is just sticking? I’ve heard even new needle valves can be problematic.
I have Weber IDA3C.
Here’s the gauge I bought. Not cheap. But it does come with different needle valve shims.

[brant]

I always have the car running
Why not follow the directions

I use two at the same time. so it goes quicker

[scrz914]

I always have the car running
Why not follow the directions

I’ll end up doing this eventually. Just trying to avoid running the engine right now as I’m diagnosing some other issues. Was just hoping to get carb and ignition settings close before running the engine. I forgot to say that the engine is newly rebuilt and is on a run stand in my garage.
Thank you though.