mamba 25 high powered brushed help

hi


just started running a 370 brushed motor on my mamba 25 ESC have set it up as per instruction and have wired it up correctly

the motor runs fine but on the track but it gradualy gets slower and slower

the motor isn't to hot (you can hold it in your hand) and the ESC is only warm

i have tried a differnt motor and the same happens

ESC running to latest firmware

any one have any ideas