I just moved into a house that has a in-ground pool, and I have a question on the polaris

The lever that I turn to choose polaris or skimmer, should this be half way, so both work?
If so the polaris seems not to be working very well. I have taken it in and had it rebuilt, cleaned all the filters, but it doesn't move very fast and seems not to be sucking. If I have the lever only on polaris only then it works great for awhile, but then the pump stops like it's getting full of air,is there something I should look at?

I know this is a 1000 things could be wrong, but thought I'd ask the people who know for some direction.

Thanks

Welcome to TFP!

I'd suspect it needs to be somewhere between halfway and all the way so you provide enough water for the cleaner to work without restricting flow to the pump too much. When the pump stops, it does so because it's not getting enough water.

If you have a picture of the control it might help us.