Ekos issues, ? And how to upgrade motors esc mounts etc

So I picked up a ekos and 2 p1 hulls, and miss excite in a trade deal, ekos had everything with it, stock motors escs rudder etc, I went through everything it all works but here lies the issue.... when I add throttle 1 motor starts earlier than the other, and spins faster?
Now I'm running off 2 new 5600 70c venom 2cells, a Y harness between speedos, if unplug ang just run one motor then run perfect, together not so much, anyone have a clue ?

Worse case I'll tear it all out and start over, looking for info on how to upgrade to inrunners, or even a single motor set up hanks for solutions or links