The controls on my Johnson all work fine (hydro electric shift) but the throttle and high idle lever are really hard to move, at least, harder then I've been used to on other boats. The cables don't appear to be bound up or anything, it just seems like inside the controls needs some oil or something. The throttle can easily be moved on the motor itself. My question is, can i just take off the screws that hold the cover on and put some kind of lubricant on it? There is also a "throttle tension" knob but it doesn't do anything. I can turn it counterclockwise (what the knob says should be to loosen the tension) forever and it doesn't change anything. The throttle lever just feels rough like there is no lube on it and not smooth at all. Any advise on this or how to take the throttle box apart?