I have that same exact motor on my boat. I've found sometimes I press the "ON/OFF" switch and the motor won't respond to the speed button until I press the ON/OFF button again. You can turn the motor off by pressing the "-" on the speed button until the motor quits and then press the "+" button to start again without pressing the ON/OFF button, which is what I usually do. This unit could use some sort of indicator light to tell when the unit is on or off.... but all in all, I love mine!!!