15 minutes to get to only 3/4 of your max is taking too long.
I use a Encore also and also now use the oversize tube. I have always been able to get nearly 1" MORE than normal max erection length. I am pretty sure most all successful pumpers get MORE length when pumping than with a normal or other erection.
With that said, and the first thing to improve might have been the tube too small -- but you did try the oversize tube (which is 2" ID)...
The next thing would be -- have you trimmed or shaved everything off?? A good seal is the next improvement (using astroglide type of lube for a seal). Complete shave is better than close trim but definitely get rid of as much as you feel comfy with.
Finally, an electric Encore pump is self-limiting at a pretty safe vacuum level, but sometimes it will cut out sucking too soon. What happened to me once was that lubestuff got into the pump and caused it to stop sucking at too weak vacuum (you can tell this by the sound of the motor which will go from a growl when pumping to a whine when just spinning and not pulling any more vacuum). I solved that once by dribbling a little rubbing alcohol directly into the pump -- it fixed the problem and have not had that problem for years since.
If you don't have the battery pump version then not sure what else -- except trimming/shaving might be even more important for manual pump.
One final thing to note is that, for me at least, pumping goes thru a stage where you do stall at maybe 3/4 max size for a few minutes and then it will quickly break thru that barrier and quickly go to beyond max length -- I guess you are not making that jump. Also even at the 3/4 max there might be a little discomfort where you have to back off vacuum a little and then go some more. If you are not having a little discomfort then you are not getting enough vacuum -- which leads us back to the original ideas of shaving and good vacuum draw.
Post Edited (JStars) : 11/4/2014 7:50:38 PM (GMT-7)