Mercury Mercruiser Drive System

Mercury Mercruiser Propulsion System Parts - Information & Resources

Over time and heavy usage, your Mercury MerCruiser drive system may experience wear and tear. A poorly performing drive system, including the lower unit and other moving parts, means that you’ll gradually experience loss of RPMs, erratic steering, uneven wear, and - in extreme cases - a completely unusable boat. That’s why it's so crucial to regularly maintain your MerCruiser during every 100 & 300 hour service interval to troubleshoot where your engine may need work - especially because many drive system problems are not easy to spot from the external engine.  

Check out some of our helpful MerCruiser resources to find what you need to know about your MerCruiser, inboard, and sterndrive motors:

• MerCruiser Inboard Maintenance
• MerCruiser Maintenance Parts Library
• Mercury Outboard and Mercruiser Resources Collection

PartsVu offers the following Mercury MerCruiser Drive System Parts and Mercury MerCruiser Drive System Kits:

• U-Joint and Components
• Gear Repair Kits - Driveshaft Housing
• Gear Sets - Driveshaft Housing
• Gear Repair Kits - Gear Housing
• Seal & Bearing Kits - Gear Housing
• Seal Kits - Driveshaft Housing
• Seal Kits - Gear Housing

Mercury Mercruiser Drive System FAQs

How can I best maintain the optimal performance of my MerCruiser lower unit?

Changing the gear lube of your MerCruiser motor is essential for ensuring its longevity and smooth operation. Having the parts and products on hand makes performing this critical maintenance step a breeze, which is why a MerCruiser marine gear lube kit is a smart and convenient way to keep your MerCruiser motor running smoothly for years to come. Here are a few reasons why you should change your oil:

1. Increased MerCruiser Lifespan - Your MerCruiser engine begins to degrade from the moment it leaves the factory and accelerates through use. This is especially true if your engine is used heavily at high RPMs, is allowed to corrode, experiences improper long-term storage, and a lack of observing all regular maintenance intervals.
2. DIY MerCruiser Repairs Save Time and Money - With little effort over a few hours, you can change your MerCruiser oil, replace routine parts, and lube up your engine - all for much less cash and time spent in the local marine mechanic shop.
3. Change Your MerCruiser Lower Unit Oil - Oil and grease are the primary lubricants that keep your outboard in the water and out of the repair shop. PartsVu.com’s MerCruiser marine gear lube kits ensure you have the right kind of oil for your engine at premium quality. 
4. Maintain Regular Outboard Service Intervals - MerCruiser motors require regular maintenance to stay reliable out on the water and avoid breakdowns. This maintenance must occur after 20 hours of service for new engines, then every 100 hours.
5. Convenience - PartsVu.com’s MerCruiser marine gear lube kits have everything you need to perform gear lube changes and help prevent buying the wrong item or compromising on quality. This includes: Mercury brand gear lube, MerCruiser gear lube pump, and MerCruiser lower unit drain gaskets. Choose the kit that matches your particular model for the correct oil and MerCruiser parts to get the job done easily.

How do you grease a MerCruiser motor?

Greasing your MerCruiser is an important part of keeping the drive system functioning optimally and preventing excessive wear on high-friction areas. Plus, it’s an essential part of your 100-hour and 300-hour service intervals that helps preserve your MerCruiser warranty.

To grease your MerCruiser motor, load a tube of Mercury grease into the grease gun and use a trigger-activated plunger to slowly dispense the grease directly into the grease points.

Grease points are metal fittings attached to your outboard motor that allow grease to be fed into the system under moderate to heavy pressure. Because you don’t have to remove most engine components to access the grease points, they’re easy to work with. 

If you’re not sure where to find grease points on your Mercury MerCruiser, refer to your service manual for your particular MerCruiser model outboard and add grease where specified.

How do you perform a MerCruiser motor oil change?

Performing needed maintenance in a timely manner on your MerCruiser is the key to its overall longevity and reliability. The procedure isn’t complicated but can get messy if you don’t know what you’re doing. 

1. Loosen your oil filter to help vent the system.
2. Remove your dipstick, insert your oil pump, and once your oil pump is inserted into the dipstick tube, pull the oil out into your oil capture container.
3. Remove the old oil filter the rest of the way.
4. Prep the new filter for installation by applying a light film of oil onto the face seal of the Mercruiser oil filter.
5. Thread the oil filter onto the oil filter mount and hand tighten.
6. Remove your Mercruiser’s fill cap and insert your funnel to prepare to add the new oil.
7. Fill the engine with the recommended oil with the proper quantity of oil—4.5 liters for a 4.5L sterndrive and 4.7 liters for a 6.2L sterndrive. We recommend using Mercury 25W-40 Synthetic Blend Oil; however, you can use Mercury 25W-40 oil.
8. It’s a good idea to run the engine with the proper water supply to check for any leaks and make sure that the proper oil level is maintained.

To avoid a big mess, use one of our MerCruiser service kits to perform a quick and easy MerCruiser oil change.

For more info, refer to our Mercruiser Oil Change In 8 Easy Steps article and to verify any details that may pertain to your specific engine model, please refer to your Mercury Mercruiser owner’s manual.

How do I use MerCruiser schematics?

If you’re looking for in-depth information for maintaining and repairing the drive system of your MerCruiser engine, PartsVu offers MerCruisers Engine Schematics and our helpful article, “How to Select the Right MerCruiser Parts”. 

After you’ve read our article and have the schematics on hand, start browsing the Mercury MerCruiser schematics page. Once there, you will choose the right parts for your MerCruiser by searching either by your outboard’s Primary Identification Number (PID) located at the top of this page or look up your model using a series of dropdown menus on the left side of the page.

There are also a wealth of helpful videos on Youtube and other video platforms. While you may not be able to find your exact engine model, you can gain real insight into what work is involved to resolve your issues, plus great tips that you would only learn from experienced Mercury marine mechanics.