Logo
FULL SITE MENU

Lower Unit Install

J

jsl

New member
I have a 2001 Mercury 90 Outboard. Recently changed the impeller but cannot reinstall the lower unit. Boat was in neutral when I took out the LU. Any help is much appreciated. Thank you.
 
Forgot to mention that it is a 2 stroke motor - don't know if it makes a difference but thought I would throw it in there. Thanks again.
 
Is it getting most of the way there then "hangin' up" with maybe an inch or so to go??

If so it's probably just the splines on the driveshaft not in sync with the crankshaft.

I know the unit is heavy so you need a helper. I find it easiest to remove the spark plugs and have a helper move the flywheel by hand once you get the driveshaft up where it belongs but it won't quite engage.

Might be a little tougher since you did this in neutral. If you had of removed it in reverse then moving the prop would have the same effect since the propshaft is "locked up" when in reverse.

Once the splines are lined up it should slide into place.

If you haven't done so you may want to put some high speed bearing grease on the drive shaft splines, just don't get any on the top of the shaft (splines only) - you don't want to cause any additional stress/load on the bottom of the crank - can shorten the life of any number of bearings, but without the grease on the splines, they can freeze into the crank - not good either...
 
Thanks for the reply and willingness to help, Graham. The LU is about an inch out to where I can't get the nuts into the screws. I will try turning the driveshaft and see if it will slide into place. I did it in neutral because that was what was done on the YouTube video I watched and I also asked a mechanic at Basspro. I did grease the splines and made sure no grease was on top of the shaft. That much I learned from YouTube. Thanks again for the help. If it works, my kids and I will thank you for the help.
 
Back
Top