battery comp. aft cg

Okay, obviously I'm doing something wrong here. I built 2 mini Arrows out of Dollar Tree foam board and they came out perfect! Once I mount the recommended Emax 2300 motor, 30A ESC, Lemon Receiver, and a 3S 1300mAh battery shoved all the way forward, that's where it all goes bad. The CG is...

Hi guys I am building my first ARF and have it almost finished. I am using an electric motor and 3s battery as I have that in my kit so the guy at the model shop gave me the biggest about 620 with an 11/5 prop I think. I put the marks on the wings for CG at 86 and to my horror it fell backwards...