I was thinking about this some more and I decided to open a brand new E2 and fill it right out of the box with no prep just to see what my results were. Here is what I did...
1. Popped carto out of the foil pack
2. Removed soft cap
3. Removed second ring
4. Removed the filler ring (Some may call this something else. It's the one with the 2 tiny fill holes)
5. Dripped 5 drops down 1 side, not at the point where the wick is
6. Dripped 5 drops down the other side, again not where the wick is
7. Repeated 5 and 6 for a total of 20 drops
8. Touched the end of the bottle to the center of the wick just to get the last little bit of fluid that did not go back into the bottle.
9. Replaced the filler ring
10. Replaced the white cap (I did not replace the middle ring. I'll explain why)
I took 3 big 8 second hits on this carto and it hit like a champ. Actually, the third hit was the best because I think the primer fluid was gone by then. I did not replace the middle ring because I wanted to be able to see if there was any leakage from the filler ring. There is not. There is however quite a bit of condensation around the cup under the wick.
I hit this carto 3 more times after only 30 seconds and all 3 were good strong hits. After another 30 seconds or so, I hit it again 2 more times and both of those hits were really good. I had to take a break and type some after that. 8 big hits in like 2 minutes got me a little amped up. lol.
Here is what came to mind about the OP situation while I was doing this.
1. Maybe your box of cartos have more primer fluid than others. This may explain why you are not getting a lot of juice in there and why the flavor is weak. After you drip some juice in there, and some gets on the wick, the flavor dissipates leaving just the primer which has not burned out yet. The primer fluid can also slow down the wicking since the wick is technically not dry.
2. After noticing the condensation, I checked the threaded end and there was also condensation on the batt. Maybe some of the leakage issues mentioned in the OP was due to condensation. With regular vaping, I have not seen that issue. But, if your normal vaping style is to take a lot of long drags in a row, you may see more condensation than I normally do.
OK, 2 more big hits and I just started to taste the first hint of the atty which means the carto is getting dry.
Waiting 5 minutes....
And finally, 1 short hit to confirm that the carto is dry. Got a little bit of vapor and flavor but mostly tasted the atty. So, time to refill.
I hope this info helps.
Edit to add: I refilled with 18 drops and the carto is firing like a champ again.
