I have OEM HU to my 90 HP. 2 problems I am facing. 1) When I rotate V C knob, instead of increase in volume it falls down. I mean if volume is at 9, it jumps down to 6,5 or 4. If I rotate knob steadily volume goes up. If I raise with little bit urgency it goes down. 2) Stored FM station automatically delete while HU is ON. & HU again starts to make autosearch.