Just got a 4 cylinder older Merc 50 HP,(with Distributor), and I am trying to get cables adjusted for shifting and throttle, but I am stuck in forward, despite all my attempts to find neutral or reverse. When the linkage is disconnected I can move the part that the shifter connects to, but I'm still stuck in forward only. It seems to have 3 positions, but all result in forward??? Any Ideas please!!!! 