How to check lower unit oil in mercury outboard

Find your trim pump. Locate the top vent hole oil plug on the lower unit side case.

Remove the oil vent screw and washer from the right side of the outboard just above the anti-cavitation plate.

How to check lower unit oil in mercury outboard. Mercury lower unit oil changes are an important part of maintaining an outboard motor. Changing the lower unit oil of a Mercury outboard provides the proper lubrication for the internal components of the motor while removing normal shavings from the oil. Also having a look at the oil during a Mercury outboard lower unit oil change will give.

As with the outboard lower unit the oil is best checked when the motor has been running recently or is allowed to warm to its normal operating temperature. Locate the dipstick usually screwed into the gear case oil filler on top of the gear case marked Oil. Take a look at the stb side of the gearcase.

Lower unit and you will see two plugs that screw into the drive number 17 in the diagram. To check the drive oil remove the upper plug. Oil should leak out.

If it doesnt you are low on gear oil. If it is milky there is water in it. Mercury recommends changing the oil in your outboards lower unit after every 100 hours of use or once a year at the very minimum.

Watch the video above and follow the steps below to replace the gearcase oil in and pressure test the lower unit of a Mercury 40HP outboard engine. Consult your outboard owners manual which I hope youve read or at least saved somewhere for the exact oil check routine for your motor because each brand and model is a little different. For example youll want to check Mercury FourStroke 115 oil level with the engine cool but a Yamaha 115 should be at operating temperature before.

Checking level of lower unit oil Welcome to iboats. Both screws in the lower unit topVent bottomDrain need washers or rubber O-rings. Some lowers use washers some use O-rings.

If the screw has threads that go all the way to the screw head youll use washers. If the screw shank has an unthreaded area just below the head youll use O-rings. Milky lower unit oil means you have water in the oil which means youve lost a seal somewhere.

The first place to look is the output seals which are found behind the propeller. Theyre commonly damaged when fishing line gets wrapped around the prop shaft and the seal can be inspected by removing the prop. Place a drain pan directly under the lower unit.

Locate the top vent hole oil plug on the lower unit side case. Refer to your owners service manual for its location if you have trouble finding it. The vent hole plug will be high up on the lower unit case and marked accordingly.

The screw plug will sit countersunk and have a large slot screw head. Find your trim pump. The easiest way to do this is by following the oil line from the tilt system back toward your tilt control or from your tilt control.

While the pump is located in different places on different boats with a Mercury outboard its usually tucked under some deck access plat in the rear of the boat. Unscrew and remove the drain plug located near the port-side bottom of the lower unit using a Phillips screwdriver. The oil might drip but it wont really flow out of the lower unit until you remove the vent screw.

Remove the washer from the screw and place the. The lower unit plugs are magnetic so you might see some metal shavings which indicate wear. If you only see a few theres nothing to worry about but an excessive amount should cause concern.

Remove the Top Plug. By removing this plug you vent the lower unit ensuring that the oil drains faster. Mercury Four Stroke Outboard Lower Unit Oil Change 40hp 50hp and 60hp - YouTube.

Remove the oil vent screw and washer from the right side of the outboard just above the anti-cavitation plate. Put a drain pan under the lower unit then remove the oil drainfill screw and washer from the right side of the outboard at the bottom of the gearcase. Whats more convenient than using our simple Mercury Direct Online Diagrams to shop from the convenience of your home.

Simply enter the original model or serial number assigned to your outboard motor by Mercury Marine. Mercury uses a specific system when assigning either serial or model numbers to their Mercury Outboard Motors however either of these can be used to lookup OEM parts. With all old oil drained you can now connect the pump adapter to the lower drain hole and your bottle of oil and start to fill the lower unit.

Youll be able to tell that its become full when you start to see oil dribble out of the upper vent plug hole. Changing the Lower Unit Oil. The lower drainfill plug screw is usually located on the starboard side of the lower unit beneath the bullet-shaped portion of the lower unit housing.

Locate your drainfill plug screw and adjust the trimtilt of your outboard motor or sterndrive so that this plug is in the lowest position possible in order to drain the used oil thoroughly. Fill the lower unit with the proper oil. That would be Outboard Lower Unit oil you fill from the bottom hole till it comes out the top hole oil level and air bleed hole.

You should buy or get an manual from the library to do this job. Or bring it in an have it done. Parts will be around 50 plus one two at tops hours labor.

Mercury Premium SAE 80W90 Gear Lube is recommended for lower units for outboards below 75 horsepower. Mercury Premium SAE 80W90 Gear Lube should not be mixed with Mercury High-Performance SAE 90 Gear Lube. Engineered to provide maximum protection for sterndrive and outboard lower units.

Reinstall the oil drain screwbolt and its washer or O-ring and wipe away any oil from the lower cowling and the lower unit. Tilt the outboard to the vertical position if it isnt already. Put a shop towel or rag under the oil filter to catch the oil that spills out when the filter is removed.