Evinrude Outboard Motor Lower Unit Oil Change

Time to change the oil in the lower unit of my Evinrude 30 horsepower outboard motor. The last time the oil was changed was probably 6 or 7 years ago when the water pump was changed and a new powerhead was installed.

While my wife and I were in Jasper, Texas taking care of some business, we stopped by the Evinrude dealership and got some gear oil. The guy behind the counter handed me a package with a bottle of oil and a pump. The oil was Mercury brand name, SAE 90. I asked the guy if it was ok to use on Evinrude and he said yes. The shop is an authorized Evinrude dealership, so I took his word for it.

The drain the oil of the Evinrude lower unit there are two flathead bolts. An oil drain pan was grabbed from the shed and placed under the lower unit. The bolts were in so tight, I had to put a pipe wrench on the screw driver to break the bolts loose. Top bolt was removed first, then the bottom bolt.

Outboard boat motor lower unit gear oil

Good news, the old oil did not have any signs of water or metal shavings in it. Nor were their any metal shavings on the drain plug.

The oil was left to drip for around an hour, or maybe more. To make sure as much oil as possible was drained out of the Evinrude lower unit, the motor was moved side-to-side and up and down several times.

After I was sure as much of the old oil had drained as as possible, the pump was connected to the lower unit and the bottle of oil. Some of the YouTube videos I watched said to pump the oil very slowly, so that is what I did. Oil was was slowly pumped into the lower unit, with breaks taken every few minutes. Eventually oil started coming out of the top hole.

Debris was removed from around the vent hole, and the gaskets on the plugs were cleaned with a paper towel.

The motor was left alone for a little while so the oil level could stabilize. Then the bolt was threaded into the vent oil, the pump was removed from the lower unit, and the drain plug reinstalled.

Evinrude lower unit oil change

When removing the bolts, they were threaded in so tight I could not break them loose by hand. The tighten the bolts back up, the pipe wrench that had been used to take them loose was used once again. The bolts were tightened hand tight, the wrench put on the screw driver, and the bolts tightened around a 1/4 – 1/2 turn more.

Overall, changing the oil in an Evinrude 30 horsepower outboard boat motor was a lot easier than I had expected.  Typically, the oil is changed when I put the boat in the shop to change the water pump.  Since it had been several years since the last oil change,  I decided to go ahead and do it myself.

I was very happy there was no water in the old oil.  That means the seals have not leaked. The o-rings around the vent and drain plugs looked good, they were not replaced.  I asked the guy at the Evinrude dealership and replacing the drain and vent o-rings, and he said typically they do not need replacing.

Next thing that needs to be done is to clean the spark plug.  Hopefully, I can get around to that in the next couple of days.  The goal is to put the finishing touches on the boat and have it ready to take out on June 30th.  I want to put the boat in at Bevil Port off HWY 63 just west of Jasper, then take the Angelina River down to Steinhagen Reservoir. That is going to be an all days trip and I want the boat to be in top condition.