I replace the water pump impeller and reinstalled the lower unit. I do not have a neutral and the shifting lever does not want to go forwar. How do I determine the neutral position of lever and spline in lower unit?
Re: 50 merc shifting problem after replacing impeller
Pull the lower unit back off. Shift the power head into forward. With the lower unit on the bench you can turn the shift shaft (the small splined shaft) left or right. The center position is neutral. In neutral the prop will rotate in either direction. In forward the prop will rotate clockwise freely but will not turn counter clockwise. In reverse the opposite is true, the prop will turn CCW (it may click like a ratchet) but it will not turn clockwise.<br /><br />Your problem is probably with the reverse lock cam. If it is in the wrong position it will probably bind on the rod which activates the reverse locks. When reinstalling the L/U you have to visualize which way the reverse cam lock is turning when the shift shaft turns to reverse position. As it turns to the reverse position the rod in the upper unit must ride up the cam moving upward which in turn moves the reverse locks downward. This sounds confusing but its the best I can do without taking my lower unit back off.<br /><br />I think what helped me visualize the reverse lock cam position was I placed a small piece of wood (like a popsicle stick) in the shift shaft of the upper unit. I then moved the shift lever in the 3 positions to check for direction and distance of movement. I then had an idea of how far the shaft actually rotated (not far) and where to place the reverse lock cam so that it would activate the rod in the upper half.
Re: 50 merc shifting problem after replacing impeller
On the 1970+ 50hp LUs, the edge where the reverse cam ramp and flat come together wants to be pointing straight forward (i.e., towards the front of the boat) when the LU is in neutral.
