My Livorsi shifter was very difficult to shift and it felt to me like it snapped a cable when I tried to reverse power to get on the lift. The port Merc 496 mag ho stayed in forward with the shifter in reverse position?Also the boat starts in forward with the shifter in any position. Does this sound like a simple problem or big one?

If I were you, I would pull the back cap on the drive (after you drain some fluid from the drive) and look at the linkage. If the shifter linkage is moving the cable that goes from the transition block to the drive, it should be moving the linkage, shift rod and actuating the cam that would shift it into gear. Something is disconected. The other option is to pull the drive and rotate the input shaft while shifting the linkage.
I suspect the cable or linkage is broken. Not that big of deal. The neutral safety switch seems to be stuck or bypassed, allowing the motor to turn over while the shifter is not in the neutral position..

Hope that helps.
Dick

Thanks for the response. May not be as bad as it seemed.

Pull the top cap and drain the fluid, many times when the upper fails it will exhibit that symptom.

Look for metal on the magnets, that will indicate if the gears are intact.