Lower Unit

[Mr. Pike1]

Okay so every year as a right of Spring I change my lower unit the old fasion way. Drain it and fill with the old squeeze tubes. Generally speaking when I put the drain plug in I always lose a little bit of gear lube. However, this time the plug slipped out of my fingers and more then usual drained before I could seal it up.

So I guess my question is if not entirely full does anyone see any risk?

[fishnowworknever]

When I change mine, I will fill it and then let it sit over night. The next day I will open up the lower plug, get my pump tube in place, then open the top one and top it off. Usually all of the air bubbles that were floating around in there will be at the top by then and it's much easier to get it filled.

I'm not too sure how much air is acceptable in there, but doing it this way somewhat eliminates that question. I know all of the outboard mechanics say to make sure all of the air pockets are out.

[Mr. Pike1]

Speaking of the drain screw slipping out of my hand. Is there suppose to be a little seal with it? Now that I am thinking about it I hope did not loose this...My motor is a 2000 90hp Mercury.

Yikes I can't go into the season with this in the back of my mind. I may have to go to the dealer to ease my mind.

[harvey lee]

Seems to me there is but I would give your dealer a buzz.

[Eric Wettschreck]

There is a small Teflon or Buna seal that goes around the plug.

I look at things this way, oil is a lot cheaper than bearings. If you have thoughts in the back of your mind that you arn't topped off, I'd be topping it off.

Even if you have to totally drain and re-fill the lower unit it's cheaper than an overhaul. Plus, you'll have the peace of mind that it's done properly and will be able to enjoy your time on the water without thinking aboot it.

[Mr. Pike1]

Eric, agreed. Ran into one minor problem. I was going to take off the drain plug to add and while adding inspect to see if a seal. One minor problem now I can not get the thing off I think its a bit stripped.

Nelson Marine is near by so Monday I will go see if they have this part as one I do get this off may need a new one anyway. Oh well worse case scenerio I end up changing out the lower unit oil twice this year. The good news is I have plenty of time to fine tune prior to opener...but with the way its looking might see the water late next week for that first run on the water

[shizzy]

I always put the top plug in before pulling the tube out of the bottom hole. that seems to reduce how much drips out the bottom in the time it takes to get the bottom plug back in.

I also have an old oil can with a pump handle I use to top off through the top hole once I have filled it through the bottom. sure makes it easier getting those last few drops in properly.

[walleyemaniac]

Sometimes my seal sticks to the lower unit housing when I pull the plug. Check that, I don't think it will hurt anything to have an extra seal if your not sure it's on the housing they're not that thick. Mines kind of hard to tell sometimes. I always double check mine the next day too just to be safe. Put the top check plug in first helps keep alot of oil from draining out.

[JohnMickish]

For the $15 bucks it going to cost to re-do the lower unit fill Vs. what it would cost if something went wrong, I think I'd just spend the $15 and know for sure what I had.

[marine_man]

You don't want to double up on seals... from time to time I've seen them leak when there have been two.

I would invest the $15 or whatever the cost is into a pump.. it's a little more, but the threaded connection makes it a lot easier, and you hands don't smell like gear lube for a week... just a day.

Also, I would get into the habit of changing lower unit lube in the fall, before you put it away.

This way, should your gear case have a leak, you drain all the water and lower unit lube from the lower unit and put gear lube only in for the winter. If there's water in the lower unit, and it is full to the top with a water / oil mixture, there's a very strong chance that when the water freezes it will push the seals out of the lower unit and you'll have a even bigger leak.

marine_man

[slammer]

Agree with marine man. I always change mine in the fall along with new seals top and bottom even if they look good. Cheap insurance.