I have a 1993 Mercury 60hp tiller 2 stroke, has a new power head. The tiller handle works fine in nice weather, but lately using it for duck hunting it is hard to turn the throtle and almost have to use two hands and is also hard to get back down to idle, only when it is cold out. What can I do to make this smoother, my 1990 Mercury 40hp did the same thing. Thanks, Jerod