Minn Kota Fortrex Bowguard 360 (serial number O339MK00503, 36V, 112lb, purchased April 2015). The push button on top to engage the motor on/off seems to be requiring more force/depression to get it to work. From looking at the parts diagram for this model it appears there is a spring under the button. Is this difficult to replace/what I need and are there other parts I should go ahead and order/replace while in there? Thanks