Here's a tip that might help someone else in a pinch.
Received my two hole bungs and tubing from Wade for two used (but new to us) aspirator pumps for my son and me. Hooked up things today making a 5 gallon carboy the receiving carboy. Was not getting enough vacuum to pull water out of the source carboy. Checked all connections and they were fine. Saw that bung seated low in the carboy. When we pushed the bung in more, the vacuum increased. Looks like the bung was slightly small. I had solid bungs the next size bigger, but didn't want to go through all the drilling, etc.
So, I tried an O ring around the bung. Made it worse. My wife suggested wrapping a little Saran wrap around bung and put it in the carboy. It fit much better! Hooked the hoses back up and tried it, it works great!
Here's the deal: most 5 gallon carboys that I've seen are made in Mexico. They have a slightly bigger opening than my 6 gallon carboys. We tried the bung on the 6 gallon, and it fits perfectly.
Getting our pumps working made my son was especially happy. He needs to degas and bottle some Skeeter Pee that he's making for a bride's to give out to guest at her upcoming wedding. Yes, Skeeter Pee. My son had some apple wine he was originally making the the September? wedding. All of a sudden, the wedding is in May. Not near enough time for the apple wine to be drinkable, at least in my opinion. The only thing that I've made that is drinkable in an extremely short time frame is Skeeter Pee.
I have #3 stoppers coming in on Monday. Will be trying to come up with a way to use these pumps to bottle.
Wade, are those hole sizes for the two hole bung 3/8" and 1/4"? Eventually, I will try to make stoppers for my 5 gallon carboys. In the meantime, I've got a whole box of Saran wrap!