Need help with setting up GM 90 2010 speed controller
 

Hi I am a member of Mendip(Weston Supermare,UK) which is a large out door asphalt track with a main straight of about 70 meters long and I need some help on what settings I should be using with my GM 90 2010 PRO speed controller as Iam new to electric raceing as i normaly race 1/10th nitro touring.
I am running a GM 10.5 motor and am running with standard internal gearing(1.9) and the problems I am getting is that the motor is fine for about two minutes of a five minute run (good acceleration and good top speed) them the motor seems to loose a bit of power. The motor dose seem a little warm when it comes off track after five minutes. I have tried different 64dp gear ratios and cannot get the motor to run consistently for full five minutes could anyone give any advice on what settings for speed controller and what gearing would be a good starting point to try and solve my problem.