How to change lower unit oil on 1996 Mercury 115 HP 2-Stroke using Quicksilver SAE 90 Gear Lube

These instructions are for models which have both an OIL LEVEL and VENT screw at the top and a FILL hole at the bottom. May apply to other models. Sorry in advance for all the cuts and edits, the traffic going by was loud.
Requires:
- 30 Minutes of Time
- 1 Quart Quicksilver 858064Q01 High Performance SAE 90 Gear Lube
- Quicksilver 19183Q02 3/8" Fill Hole Screw Seals (4-Pack)
- Shoreline Marine Pump
- Large Flathead Screwdriver
- Container for old oil
- Paper towel/rags

[@markcross2696]

Your patient and methodical style is greatly appreciated. Really clear and helpful! Thanks again!

[@blueman841]

thanks for posting, you m Ade it clear and detailed enough, that someone with no experience at this sort of thing can do it. also appreciate your "helpers " hanging around checking on your work :)

[@keve1212]

Thanks for the video. Also thanks for the shot of the service manual - that was helpful. I still can't believe they haven't figured out a better way, and this is still the system for changing foot oil. It was always dumb and still is.

[@dmuhl84]

How is it dumb? It's the only way to ensure an air bubble isn't trapped in the lower unit?

[@keve1212]

@@dmuhl84 Your punctuation is confusing. It's not the only way. It's the only way because of how they build them. It would not be hard for a team of engineers much smarter than me to come up with a simple fix. Off the top of my head, there could be a built-in, open-bottom tube along the side of the gear housing to which you attach the oil from the top, and a 2nd vent at the top for air (which some have anyway). That's after about 15 seconds of considering the problem. Instead, we have "OK, so drain the oil, thread your fitting to the bottom drain, pump oil until it spills out the side of your lower unit, then pull it out and try to thread that tiny little plug back in there as quickly as possible as oil dribbles out all over everything, then if you lose too much, pull the drain again, losing more oil while you try to get the oil threaded back onto it, and do it all over again." That's a solution clearly designed by someone who sells oil, and it's dumb. It's practically the equivalent of still having hand cranks to start cars.

[@SB-lm2jf]

well done, young man. had to replace my lower unit in that same 115 about 4yrs ago, changed the break-in oil after about 10hrs. i just had it in the shop for other stuff, went to change lower unit oil while on the trailer. oil outta the top 2 looked fine. oil out of the bottom plug came out milky white. know anybody who sells lower units for that old motor? I'll ask my favorite boat mechanic if there's a cheaper fix but i'm prepared for the worst (again).

[@striker1211]

If the lower unit is still working you probably just need the prop seal, fishing line cuts it up. Thank you for reminding me to check my LU oil lol. My boat is down right now cuz a squirrel chewed a hole in the gas tank.

[@SB-lm2jf]

@@striker1211 is changing the prop seal a DIY project or should I run it to my mechanic?

[@SB-lm2jf]

@@striker1211 oh yeah, yes it is still running. I have noticed that if I hammer it, the proper spin a little faster than the rest of the motor intermittently

[@andrewcarmichael2412]

I literally love the chickens lol

[@sammyhash4135]

the three holes to fill from top not from the drain one. the drain one to take the oil out, then use the vent one to add oil until it full and get out of the level one. you actually overfill it when you pumped the oil all the way to the vent (Top) hole.

[@striker1211]

There is a screenshot of the service manual at the end of the video, which is what I was following. To be honest, as long as you don't get water in the lower unit and keep it mostly full you'll be fine.

[@dmuhl84]

WRONG! YOU ALWAYS FILL FROM THE BOTTOM!

[@garycoutts6821]

Good Video I'll be changing the oil on my 1976 115 2 stroke evinrude tomorrow it dose not have the vent screw but pretty much the same for filling and draining thanks ive sub to your channel cheers from the Land Down Under

[@redboat5029]

love the chickens

[@ChrisThomas-tz8jr]

Good video. I believe the reason for the extra hole has to do with possible oil loss when you put the bottom plug back in. That final pump to get the oil out the top plug allows for any possible loss when putting the plug in at the bottom.

[@striker1211]

That is one of my theories too, the other theory is that it is so you can change the lower unit oil while the boat it is in the water and raised up without dumping all the oil out as soon as you pump it in. I'd love to find the actual engineer and ask them.

[@sergiomanuelgarciacaso1311]

Thank you

[@SB-lm2jf]

hey bud, i'm gonna take this old boat to my mechanic for that prop shaft seal and the water pump seal. my transom saver won't keep the motor from turning while towing. any suggestions for keeping that motor stabilized while towing?

[@striker1211]

@@SB-lm2jf I've never used a transom saver so I cannot help you there. I just turn it all the way left or right after raising it and then flip the motor lock, and lower motor down on lock.

[@SB-lm2jf]

@@striker1211 thanks for that but where is that motor lock? sorry for my ignorance

[@denniskucan9796]

The two top screws isn't one for the lincage..

[@brettwinstead]

When I tried this, something weird happened. Eventually the oil just stopped flowing into the lower unit and started seeping out the edges of the pump where it screws in to the bottle. I could not get any more oil into the motor and it would not seep out of the top section like it's supposed to. I had plenty of oil left in the 32 oz container but it just kept seeping out of the pump itself. I'm kind of getting the feeling that my pump sort of exploded even though it was brand new. Should I just get a new pump and try again? Thank you.

[@striker1211]

If you had opened the vent screws on the lower unit and this happened then yes the pumps check valve is backwards and a new pump would be my next step.

[@hvymax]

You don't want Righty Tighty to turn into Righty Loosey!

[@mikesansonetti3443]

Mine came out the vent first. Is that normal? Nothing came out the oil level. Should I add more oil?

[@striker1211]

I'm not sure what could cause that unless the motor was tilted counter clockwise from straight.

[@justtisha]

How often are u supposed to do this?

[@striker1211]

I do it every fall to make sure the lower unit doesn't freeze if water got in. Youre supposed to do it every 100 hours or every year.

[@danielcullum8996]

Put old oil on chook legs get rid of mights ps cheers for vid

[@COSMACELF1802]

Would it help to raise the motor before removing the pump and reinstalling the bottom plug?

[@striker1211]

As long as the level is fine when you put the top plug in I don't see how it could hurt. I can't see it helping much either though because you're going to lose a little fluid no matter how fast you go.

[@scottdaup1293]

Where can I purchase a hard copy of the manual for a 2007 90hp 2 stroke

[@striker1211]

The Yamaha dealer can order them but they are expensive. I'd check on eBay if you need a hard copy. Just make sure it's an actual real copy because some shady sellers will try sending you a disc with a pdf on it. Thanks for watching.

[@scottdaup1293]

@@striker1211 thanks

[@mrsatire9475]

That's my kinda red-neck buddy right there ... screw the lawn, dig a hole just so's the motor can stand upright ... amiright?

[@striker1211]

Yup, much quicker than hooking it back up to the truck

[@c-LAW]

2:50 Say hi to Henrietta. Even to this day she's a hot chick.

[@hunterschaferoutdoors0219]

How much oil did you use?

[@striker1211]

It varies by engine size but I always just buy one quart every year. I always have a little left over.

[@markwebb2163]

Why can’t you fill from top ???! Then you don’t lose any oil !!!!

[@striker1211]

The lower unit's internal cavity design could leave air pockets if you fill from the top. The service manual also says to fill from the bottom. I imagine if you filled it from the top, then lifted the engine up and down a few times you'd get the air bubbles out, but at that point it's easier to just use the proper tool and inject the oil into the bottom hole.

[@northlanddude9515]

Fantastic video thank you!!!!!