1990 20 hp Mercury water pump replacement

[Polmsche]

I changed out the water pump on a 90-20 horsepower Mercury and there is no reverse now. I removed the lower unit again and noted that the washer that goes on the shift rod is missing. Is this part of the problem and what can I replace it with?

[boats.net]

No the washer wont stop it from shifting, probably have the shaft splines misaligned. Put both the motor and lower unit in neutral and reinstall lower unit.

[Polmsche]

Thanks. Should the control box be in neutral too?

[boats.net]

Yes get it all in neutral to align shift shaft splines.