On the problem with the rudders popping up, there should be an adjustment for that. There are spring loaded plastic pieces that go into the notches in the rudder cams to hold them in the locked position. There are Allen screws that hold the springs and they can be tightened to increase the force on the plastic pieces. Look up from under the rudder castings.

On my boat, an '85, the rudders can also be raked by another adjustment but you then have to adjust the position of the locks to take the play out of the rudders. Look for bolt heads in the slot on the top of the tiller arms. If you don't have the adjustment, there won't be a slot. You may have excessive wear or play in that adjustment which would affect the pop up of the rudders. With the rudders locked down, you loosen the bolt and slide the locks forward in the slot to take out the play in the rudders, then retighten.

Howard