Changing the Oil in the outboard engine and lower unit.

in blog •  6 months ago

Don’t let the engine maintenance scare you away from your boat purchase. After all, having a boat opens up access to new areas to kite and surf.

Plus, If you have a 4 stroke engine changing the oil in the engine and the lower unit is easy peasy.

You do need to get the boat out of the water to do this. Once on the trailer on dry land make sure you have all the necessary supplies.

Supplies needed:

Oil filter- follow manufacturer specs for this
adjustable wrench
oil extractor pump
flat or philips screwdriver
container for used oil collection
paper towels
replacement oil

Most people will have all the above supplies with the exception of the oil extractor which can be purchased at most auto parts stores and at all marine supply stores. The cost of your typical oil extractor is between $40-70 USD. Thankfully this will be a one time purchase.

First remove the engine cover to access the engine parts

Start by removing the oil cap and placing the oil extractor hose inside and vacuuming out the oil. The extractor has a handle on top that will maintain the pressure of the vacuum to remove the oil.


remove the oil cap

extractor hose in oil reservoir

oil extractor

oil extractor

Once the reservoir is full you will need to dump the used oil into a container and follow your local policies for environmental disposal of use engine oil. In the US you can take the used oil to the recycling center where they are able to re-purpose the used oil.

You may have to fill the reservoir several times to remove all the used oil.

Next you remove the old oil filter. For most outboard engines this requires using an adjustable wrench for the first turn. Be aware that there will be oil remaining in the filter. Have paper towels ready to catch the spill or have the container for disposal close by.


Place the hose for the oil extractor where the oil filter came out to remove all remaining used oil.

Now you are ready to refill with clean oil. Screw the new oil filter in.
Using a funnel pour fresh oil in to your engine.
Take a look on the outboard to see if there is a recommended amount to fill with each oil change. The sticker you find will also usually tell you the recommended oil type for that particular engine. Most engines use 10W30 or 10W40 motor oil.

To change the oil/lubricant in the Lower unit you will need three additional supplies

Replacement gaskets
Gearcase Lubricant
Gearcase Lubricant pump

All you have to do is remove the upper and lower screws.

upper screw

*lower screw

When you remove the lower screw be ready for the oil to spill out. Have you oil can ready. It helps if you use the tilt / trim on the engine to keep the oil running smoothly out of the hole since it is on a curved surface.

Allow the lubricant to drain out.

Then you are actually going to refill from the bottom up.

Refill by screwing the gear case lubricant pump hose into the lower screw hole and pumping until the lubricant starts to spill out of the top screw hole.



watch the top hole to see when it is full

Replace the gaskets for the screws.

Replace the top screw hole first.

When pulling out the Gearcase Lubricant from the lower hole have the screw and replacement gasket ready to quickly screw back in.

And that's it!!
Check the manufacturers recommendations to see how often oil changes are recommended.

Now go buy a boat already.

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