MerCruiser Out Drive Oil

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Updated on April 2, 2022

Are you in the market for a high-performing, long-lasting lubricant for your boat’s outdrive? Check out all the MerCruiser outdrive oil has to offer to your boat’s overall performance.

The MerCruiser outdrive oil is an extreme pressure lubricant designed for MerCruiser 3 engines. Most engines in this range are rated at 135HP and have a displacement rate of minimum 3 liters.

Deciding to place orders for this oil shouldn’t be borne out of flashy ads: you need real info before purchasing. That’s why this guide provides essential information on the MerCruiser outdrive oil and all its interesting features.

Taking cues from this post makes it easy to lube your boat’s outdrive with ease!

What Kind of Oil is MerCruiser Out Drive Oil?

MerCruiser outdrive oil is a synthetic engine oil and is available in SAE 40 viscosity. The drive oil is recommended for filling the outdrives of different engines. 

Most engines with performance ratings of 135HP will function better if lubed with MerCruiser out drive oil. 

How to Fill MerCruiser Out Drive Oil?

Step 1: Get required items

You will need a flat screwdriver, oil pump, and drain pan to fill MerCruiser out drive oil into your boat. First, place the drain pan under your boat’s outdrive to prevent any leaks or seeps that may cause accidents. 

Step 2: Open side oil plug

Next, use your screwdriver to open the side vent of your outdrive (other models may have this placed differently).  Proceed to check the outdrive for any oil (with a dipstick or your finger based on its level).

Next, drain out all the oil in your boat’s outdrive onto that drain pan you placed underneath earlier. Allow all the old lube to drain out before going on to the next step. 

Step 3: Pump oil into outdrive

Place the lube pump in the oil can and put its hose into your outdrive. Make sure the drain opening is tightly sealed to avoid leaks of your new outdrive oil.

Gently pump the oil from your lube can into the outdrive. Stop filling the outdrive when you can see lube coming out from the side opening. 

Step 4: Tighten oil plug screw

Use the screwdriver to securely fasten the oil plug to prevent water penetration and leaks during use. You can also check the reservoir monitor and drain out old oil before filling it with lube. 

MerCruiser Outdrive Oil Reservoir Location

The oil reservoir for a MerCruiser engine is usually located few inches away from its outdrive. An outdrive oil reservoir will usually be fastened onto a metal adapter on your boat with screws. 

Some models have the reservoir located at almost the same level with its outdrive. Other versions have this monitor located slightly higher than the engine to act as its oil level sensor. 

How Much Gear Oil in a MerCruiser Outdrive?

An Alpha One Gen II MerCruiser outdrive can hold around 1.75-quarts (56 ounces) of oil. Other MerCruiser outdrive models can hold anywhere within 1.22-quarts (39 ounces) and 29-quarts (7.3 gallons) of oil. 

MerCruiser Outdrive Oil Specifications

MerCruiser outdrive oils are fully synthetic, with a 20W-40 viscosity rating for most standard engines. The drive oil is best suited for MerCruiser crankcases with air temperature ratings pegged at or below 32°F. 

MerCruiser Drive Oil Reservoir Cap 

The MerCruiser drive oil reservoir may develop issues with containing gear lube after prolonged use. Leaky washers commonly plague old MerCruiser drive oil reservoir caps.

In other cases, the cap’s valve could become leaky along with its washer. Some extreme cases may see the reservoir cap split in two after long periods of use. 

Luckily, replacement reservoir caps are available in stores to fit any MerCruiser drive oil monitor. Most options on the market are available for under $10.

How Much Oil Does a Bravo MerCruiser Outdrive Take?

A Bravo One MerCruiser outdrive can take about 2-quarts (½ gallon) of gear lube. Also, a Bravo One MerCruiser outdrive (Round Lube Monitor model) can take about 3.25-quarts (104 ounces) of oil.

What Weight is MerCruiser Drive Oil?

The MerCruiser outdrive oil is available in its standard SAE 20W-40 weight. It is also available in thicker weights to about SAE 90. 

The SAE 40 viscosity rating is designed to work well under very high temperatures. High motor-load situations can also be properly lubricated with an SAE 40 weight oil.

Most high-performing engines with ratings over 100HP need a gear lube that provides improved oil film adhesion. The MerCruiser drive oil provides the elements required to support smooth gear case operation.