Water in Lower Unit

[snyderpf]

Hello Folks, I changed my water pump impeller per the shop manual (and a couple of UTube videos) with no problem. Also changed gear oil in the lower unit at same time. After 40 minutes of running - something was wrong - vibration - and we trolled back to the freshwater dock. At home, drained unit and it was maybe 50 % water. Any idea as to what I did wrong? What damage I can expect? Unit is a 115 hp 4 stroke now 10 years old, mostly in freshwater.
Many thanks - Paul in SC

[Solarman]

If you apply a little air pressure, small hand type air pump, a soapy solution around shift housing, around drive shaft seal & housing (under water pump flat plate), and around prop shaft & housing, as well as the fill and drain plug holes, something should show some bubbles. Yes, this does mean removing lower unit again, but you can test the drain & air vent plugs, and prop seal & housing before removal. The shift rod & housing and drive shaft seal & housing require lower unit removal for test.

Good luck, post back if find anything.

[artdf175]

Moonlighters suggestion is right on
but.. he didn't tell you where to apply the air pressure

I would start with the vent screw for the lower unit oil fill..
lower the output pressure on your compressor so you don't blow out any gaskets and watch for leaks
if you have had the lower unit drive shaft out there is a 'o' ring in there that may have not re-seated correctly
check for the obvious first
you did change the washers on the two screws for the lower unit oil fill and vent? important to use new ones ..

Art

[catacom225]

Water

I would think you may have left the washers out, stranger things happen
Just doing an impeller should not cause a major oil breach

[Scottf]

Are there any videos or directions on changing lower unit seals?
i have a 2010 DF300

[Moonlighter]

Also, check to ensure that you replaced the washers on the gearbox drain/full level screws. Wouldn’t be the first time someone forgot to put them back on, or, put the new washer/s on over the top of the old one. Water then gets in.