First time doing this myself. 2005 optimax 200 hp. I cant find any you tube videos putting the lower unit back on. Is this a problem? Cant i turn the prop by hand while i work the drive shaft spline back on? Is the shift rod straight forward to line up ? Any other tips for a first timer or better yet a full video?

Been a while since I’ve done it, but it’s really a 2 person job. You need someone to rotate the flywheel until it splines in from the top. At least this is how I remember it. Could be wrong, but I remember someone turning something from the top.

Wont turning the prop move the lower unit spline and do the same thing?

Don’t spin the prop, mark the spine and housing, so they are pretty much in the proper place when you go to stab it back in there. Can be challenging or it can go right in. Pay attention to how you take things off and don’t lose the key way (or whatever that little half moon keeper is called)


Sometimes you’ll have to put the control lever in gear, for it to go back together.

If I do need to move the flywheel can i do it by hand? I am a little apprehensive trying to bump it with the ignition key

Should I pull the lower unit off while its in gear?

Pull the prop and then the only time you might spin the shaft is while putting the impeller & housing back on.

Remember that you have a speedo hose to disconnect and have to pull the torque tab to get to the back bolt. I’m certain there are you tube videos on this.

The guy that did my lower unit used a ratchet strap that ran under the cavitation plate and up to each side of the motor to hold it in place. Then he easily tightened it into place so he could bolt it back on.

I used a longer bolt where the trim tab goes. Worked for me. I probably replaced 10 on my Black Max and always put it in forward gear. I could do the Black Max pretty easy by myself. Probably 3 or 4 times out of 10 I would knock the shifter out of gear. On the Optimax make sure you use the little plastic tool to seat the gasket on top of driveshaft. On the Optimax I had a harder time getting the shift shaft to line up. You don't want the shift shaft out of synch.

Make sure you don't put the impeller in backwards.

How are you guys sliding the impeller over and down the shaft, if the shaft is still up in the motor? I’m not understanding this “hanging lower” theory.

Does the shift linkage only line up one way so its obvious if it isnt correct? I cant find any videos on this putting it back together.

Yes, pretty much. The lower unit should fully mate up by hand to the mid section (no gap) when shift linkage is lined up correctly. If not, do not force it.

I did my 115 optimax for the first time. I've seen both recommendations as whether to leave it in gear or neutral. I left mine in neutral. Put it back together and couldn't get spline to engage. Bumped ignition but that didn't work. Took cowling and moved flywheel by hand and it went right in.

If the shifter on lower unit does not properly mate up with the shift rod on motor and you tighten it up you will cause some issues up top.

Which direction does the flywheel move

I don't remember. Just had to move it enough for splines to line up - less than 1/2" so I don't think direction matters?