Changing lower unit lube

Discussion in 'Bubba's Outboards' started by Bobpaul, Dec 5, 2005.

  1. Bobpaul

    Bobpaul New Member

    Supply NC
    For those of you who have never changed your lower unit oil, this should clear things up, I hope.

    A large common screw driver. For some you may need a hand impact tool with a large common screwdriver bit.
    A shallow pan to drain the oil, and will hold nearly 1 qt of used oil.
    A pump that can be bought at Wal-Mart that will screw into a 1 qt oil container w/clear plastic hose and an end that will screw into your lower unit fill hole. I can't find one that will screw into most Japanese models or Mercs.

    Rags for clean up.
    At least 1 qt of lower unit outboard lube.

    Now proceed;
    Remove the two screws that your large common screwdriver will fit. One will be at the top above the anti-cavitation plate and the other will be at the bottom of the lower unit gear housing. Don't remove or turn any screw with a Phillips head.
    Recently some engines have come out with the top screw that does have a cross head that a common or large phillips will fit.

    Remove the top screw FIRST. That will relieve any pressure that might have built up and not blow oil in your face when you remove the bottom screw.

    Let the oil drain. If you get water out first then you may need to have your lower unit pressure/vacume tested To find out what seal might be leaking.

    If no water and just some of the most fowl smelling oil there is, then you'll be ready to fill it after it finishes draining.

    Screw the pump into the bottle of oil.
    Screw the other end of the attached plastic tube into the bottom, drain hole.
    Now pump the oil in until it comes out the top hole.
    Install the top plug.
    Get the bottom plug ready to crew in and unscrew the plastic tube then quickly install the bottom plug. You won't loose much oil unless your a total clutz. In that event, start over again, and do it till you get it right.

    Get rid of your old oil responsibly and clean up the mess
  2. spoonfish

    spoonfish New Member

    Warsaw, Mo.
    A little trick I learned is to go buy a small farm weed sprayer, the kind that pump up and have a trigger sprayer. Take the tip off the sprayer arm and place a foot or two long piece of clear hose on it. Place a male fitting that will screw into your lower unit on the other end of the hose. Pump it up, screw the fitting into your lower unit and hit the trigger. When the oil comes out of the top hole release the trigger and its full. Very little mess this way and very easy.

  3. Bobpaul

    Bobpaul New Member

    Supply NC
    Troy, I think a 1 gallon sprayer is about the smallest you can get. They do make it easy and are much cheaper than the commercial oil change type tanks.

    You don't really have to get a male end for them, but it's nice, just hold the end into the lower hole with some pressure and it won't leak oil.
  4. jim

    jim New Member

    Jacksonville NC
    Thanks as usual Bobpaul.I would just add that Lubrimatic makes a synthetic lower unit oil that doesn't cost much more than the regular version.I change mine every 4 months and feel it is cheap protection/prevention same as changing my trucks oil every 3500 miles.
  5. Nobody Special

    Nobody Special New Member

    I always did it without a pump. I cut the tip off the spout on the bottle, hold it tight into the hole and squeeze the bottle til it's flat.
  6. turtle1173

    turtle1173 Member

    Mayfield, KY
    Excellent Info Bob Paul. That is certainly some maintenance that just about anybody can do.

    I would only add that it is a good idea to replace the gaskets on the "Fill" & "Vent" screws. You don't want to go through all that and then get water in the Lower Unit because you re-used a gasket that should have been replaced. They are some inexpensive insurance.