Yep, Just messed with mine yesterday. 1/2HP convertible pump sitting on top of the tank in basement. Shaft seal started leaking a little a while back. Got the seal kit, but putting it off cause if something goes wrong I am screwed with limited ability to get a similar setup in store. I ordered one in to Home Depot. First one came in damaged and they got replacement sitting there as of a few days ago. But,...it's not the same one I have though. So would need to redo all the plumbing. As of yesterday, the shaft was barely leaking if at all. So decided to put off any repairs and attempt a little 'tune up'. I put on a new gauge I had bought recently. Was going a little low so bumped the cut-in up to 20. I used a tire gauge and checked bladder pressure. It was about 15 -filled to 18 now. Only problem was I cant get it to 40 on top end. If I turn the nut down it just acts like it wants to run forever. I don't know if regulator works right. Tried adjusting that for max flow, but was just soaking the floor. I took a shower since then and think it had a little better pressure ,or at least more consistent.
Your tank sounds like it is water logged. Turn the pump off and let 5 gal or so of the water out. Then pump the tank up to 40 pounds with your air compressor. That will fix your constant running.
I need to find the measurements I took of the well and decide if I should get the 1/2hp at HD or go up to a 3/4. They will hold that on til 4/26...