RE: Discharging problem?
JP.
Rodney ask you if you have adequate cooling provided for the ESC or lipo. I don't think you answer him, this is very important question. I bet it is not enogh cooling since your sistem it's running hotter than before. You need to provide more air flow to them, thats why your ESC it's shutting you down after a few minutes. I did had a very similar problem with my ESC shutting me down after a few minutes and a few time I was force to a hard landing. So I move the ESC closer to the nose and open a bigger hole in the cowl for the air to flow to the lipo and problem solve. Try that first before going bigger in the rest of your sistem. Check also your amp draw of the new motor it may be over amping the ESC like Rodney said and just need to throttel manegament. If this the case then maybe you need a bigger one but try this options first.
Fernando