Mercury Outboard Engine and Lower Unit Oil Changes

Here at Boats.net, we’ve published multiple videos and articles related to all kinds of boat and outboard maintenance, repairs and troubleshooting.

Mercury outboard oil changes

Boats.net specializes in selling outboard parts, but we’ve also published many outboard maintenance and repair videos and articles. For this playlist, we’ve compiled a list of our videos dedicated to Mercury outboard engine oil and gearcase lube (lower unit oil) changes. 

Mercury 20 Outboard Oil Change

In the Boats.net video above, see how to change the oil in a Mercury 20HP 4-stroke outboard motor. The Mercury 20HP outboard oil change starts by lifting the motor up to drain out the old oil, twice. Next, see how to remove the old oil filter and replace it with a new Mercury outboard oil filter. We then refill the engine with 1.1 quarts of fresh Mercury oil. You should change the oil in a Mercury 20HP 4-stroke motor after every 100 hours of run time.

Related: Mercury 20HP Outboard Engine Oil Change

Buy Mercury outboard engine oil

Buy Mercury outboard oil filter

Mercury 25 Outboard Lower Unit Oil Change

Watch the video above to see how to change the lower unit oil (gearcase lube) in a Mercury Tracker 25 outboard. We start replacing the gearcase lube in our Mercury 25 outboard by removing the vent and drain plugs, then using a Mercury gear lube pump to fill the gearcase with fresh lower unit oil. When you see gearcase oil running out of the vent opening at the top, you know it’s full. 

Related: Mercury Tracker 25 Gearcase Oil Change

Buy Mercury outboard lower unit oil

Buy Mercury marine gear lube pump

Mercury 40 Outboard Oil Change

Watch the Boats.net video above to learn how to change the engine oil in a Mercury 40 HP 4-stroke outboard. See how to remove the cowling, locate the oil drain bolt and get the old oil drained out. Next, you’ll see how to replace the drain bolt and the oil filter, and refill the outboard engine with about three quarts of 25W40 Mercury synthetic oil.

Related: Mercury 40 Outboard Engine Oil Change

Buy Mercury outboard 4-stroke synthetic oil

Buy Mercury marine outboard oil filter

Mercury 40 Outboard Lower Unit Oil Change

In the video above, see how to change the gearcase oil in a Mercury 40HP outboard. The process starts by opening the vent bolt and the drain bolt to get the old lower unit oil out. Next, see how to check the lower unit for leaks in the seals at the prop shaft and drive shaft using a gearcase pressure tester. After the pressure test, we refill the lower unit with fresh gearcase lube using a hand pump specific to Mercury that fits the fill opening. 

Related: Mercury 40HP Outboard Gearcase Oil Change & Pressure Test

Mercury 40 Outboard Lower Unit Oil Change (Two Stroke)

Watch the video above to learn how to change the lower unit oil in a Mercury 40HP two-stroke outboard. This job requires a Mercury gear lube pump with the correct fitting. See how to drain out the lower unit oil, followed by a gearcase pressure test. After the test, we pump fresh gearcase oil into the engine before closing it up.

Related: Mercury 40HP 2-Stroke Lower Unit Oil Change

Mercury 115 Outboard Oil Change

Watch the video above to learn how to change the oil in a Mercury 115 outboard. We use a complete Mercury outboard oil change kit for this job, which is cheaper than buying the standard oil and oil filter individually. The oil change process for a Mercury 115 is pretty simple. First, we remove the cowling to access the motor. Then, we tilt the motor up in order to drain the oil. It’s important to turn the motor to the side when tilting it so that the oil drain faces the ground. Otherwise, it’s a mess. After draining the oil, we replace the drain plug and then the oil filter. We use a 65mm oil filter wrench to remove the old filter, then replace it with a new Mercury oil filter, and wrap up the job by refilling the engine with 4.8 quarts oil.

Related: How to Change Mercury 115HP Oil & Filter

Buy Mercury 4-stroke outboard oil change kit

Buy standard Mercury outboard 4-stroke engine oil

Mercury 200 Outboard Oil Change

In the video above, see how to change the oil in a Mercury 200XL Verado outboard engine. You can use either synthetic oil or standard oil for this job. Watch the video to learn how to drain the oil, replace the oil filter, and then refill the engine with 6.3 quarts of oil and set the oil level. 

Related: Mercury 200XL Verado Outboard Oil Change

Mercury 200 Lower Unit Oil Change

Watch the video above to learn how to change the lower unit oil in a Mercury 200 outboard. In many oil changes, you drain the engine oil at the bottom and fill it at the top, but not here. See where to find the vent and drain bolts, and then use a Mercury gear lube pump to force the gearcase oil into the unit from the drain opening. The lower unit is full when you see the gearcase lube running out of the vent opening at the top. 

Related: Mercury 200XL Verado Lower Unit Oil Change 

 

 

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