How To Change your Boat's Lower Unit Oil

Lenny Rudow explains how to change the lower unit oil on your boat's outboard engine. Outboard boat owners, as well as those with stern drives, should know how to do this!

[mscarbo]

you should always pump your gear oil in slowly till it comes out the top hole, then let it set ( with pump still attached ) for a few mins. to get the air bubbles out. then top off and add screws back in. just how i was taught.

[jdutube]

Simple and straight to the point, good job!

[KozarBen]

I always remove upper first, then put it back in loosely, then remove lower, not a good idea to drain the oil until you are sure you can get the top open to put fresh oil in, it's a bigger deal on car differentials but still good practice, ;). Nothing sucks like draining the oil then figuring out you can't refill it!

[Belzer]

Bought a boat from someone who never did a lot of maintenance. It’s a pontoon with a 97 Mercury. I decided to do this and the oil that came out looked like chocolate syrup and stunk so bad, it smelled like rotting meat. Unbelievable. This is something easy to do and doesn’t take a lot of time.

[davidmartins]

Appreciate you making this video. I'm going to change mine now.

[kevinblanchard]

New gasket every few years too! Thanks

[martinschulz]

I'm about to do my first lower end change on my Suzuki. I guess it surprises me that the outboard companies haven't figured out a way to design the bottom end so that the oil can be filled from the top hole like every other gear box.

[metisrick]

Great video but missed the "make sure your gaskets are good" component.

[mithflj]

Hello what about the upper part of the engine - pistons. Does this oil cover that as well.

[psychodad]

I have a Johnson 150 2 stroke and so far, I have only found one plug for the lower unit. Is the procedure the same?

[mt]

did not talk about changing the o-ring on the plugs

[Nate......]

Can you believe there's people out there with 7 &10 and even 20 minutes of a video showing how to change the lower unit oil. Their video is longer than how long it takes you to change the oil 🥴

[touu]

My magnetic drain screw at the bottom of the motor is stuck. Any advice on how I can remove it? Also, where can I purchase a new drain plug? It is a 1996 two stroke dt40.

[johnechterhoff]

Is it possible to replace the plugs with (of course) with the same sized threaded type only a type that s removed and replaced using a socket wrench?  I had a Evinrude 175 back in '88 and changed the gear lube with a big flat blade screw-driver and it tightened down fine.  Six months of heavy fishing later, I went to loosen the screws and I could not.  I want to say impossible.  I suppose the vibration from the running motor tightened it into oblivia!  LOL!  A socket would have done it!  Thanks for the good vid!  JEE.

[goosenation]

can you drain the oil before winter and then fill it back up after winter

[tylerandtony]

You have any suggestions on gear oil leaking?  Small amount, but it's leaking.  I am not a boat mechanic, obviously, but this video, is this for gear oil?

[dimseeida]

Both upper and lower oil plugs are blocked and I can't unscrew them.
Any advise?

[ortega]

Could you thread the lower nut in and fill from the top?

[psychodad]

Me again. I have my motor down from warming up the engine. I see oil coming out of the back of the lower unit. Should I drain it and take it apart to see what is causing the oil leak? Secondly, if it's a seal, where can I get it from locally or online?

[abaroun]

should i change the plug seals or keep the old ones ?