Gear box stay in forward when using reverse

[redmapleleaf]

Hi there,

I hope somebody can help me. I have a Mercury 50HP and I recently removed the gearbox assembly to replace the water pump not working. When I put them back together, the boat keep going forward even though I have put it in reverse gear. Note that neutral and forward gears are working fine.

Do you know if I have done something wrong and how may I correct it?

Thank you very much for your help.

regards,
RedMapleLeaf

 

[Tadd_P]

Re: Gear box stay in forward when using reverse

yeah does your model have a little spline gear that comes out of the lower unit and slips into the shifting rod?

 

[redmapleleaf]

Re: Gear box stay in forward when using reverse

yes, it has an extension that fit into a hole on the gear box assembly. Actually as I remember it, the extension about half an inch is from the lower unit that fit into the upper unit. This Mercury engine is a bit old (5 years plus) but I am not sure of the exact age of it.

 

[jebeebe]

Re: Gear box stay in forward when using reverse

you need to put the controls in neutral and lower the drop the lower unit and turn the shift shaft in the lower unit toward the rear until the prop will spin free and put the lower unit back up. You are at least one spline off where they couple. If it still seems not to be all the way in reverse repeat the process one more spline............Jerry

 

[redmapleleaf]

Re: Gear box stay in forward when using reverse

Jerry,

Thank you, I'll try your suggestion. Could you clarify what you meant by "turn the shift shaft in the lower unit toward the rear until the prop will spin free". What is the "shift shaft" and how to "turn it to the rear"?

regards,
Redmapleleaf

>>you need to put the controls in neutral and lower the drop the lower unit and turn the shift shaft in the lower unit toward the rear until the prop will spin free and put the lower unit back up. You are at least one spline off where they couple. If it still seems not to be all the way in reverse repeat the process one more spline............Jerry

 

[jebeebe]

Re: Gear box stay in forward when using reverse

Jerry,

Thank you, I'll try your suggestion. Could you clarify what you meant by "turn the shift shaft in the lower unit toward the rear until the prop will spin free". What is the "shift shaft" and how to "turn it to the rear"?

regards,
Redmapleleaf

>>you need to put the controls in neutral and lower the drop the lower unit and turn the shift shaft in the lower unit toward the rear until the prop will spin free and put the lower unit back up. You are at least one spline off where they couple. If it still seems not to be all the way in reverse repeat the process one more spline............Jerry

The shift shaft is the spline sticking up out of the lower unit at the front. Turn it ccw till it clicks and you can spin the prop in both directions freely. you will then be in neutral . Then with the controls in neutral join the lower unit back up, making sure the upper shift rod and the shift shaft are coupled in their splines, and the drive shaft goes up in the motor and water tube is in place and you should be good to go..................Jerry

ps If the driveshaft doesn't want to go in.......pop the hood off and turn the flywheel a little and the splines will line up and go.