Mercury Mercruiser Internal Engine

Mercury MerCruiser Internal Engine Parts - Resources and Information

Your MerCruiser internal engine components are some of the most important parts of your engine - and keeping them in working order is absolutely essential for the best performance, year-after-year, reliability, and the safest experience out on the water. 

PartsVu offers Mercury MerCruiser boats all of the internal engine parts MerCruiser boaters need to perform their own repairs. We carry model-specific parts, like a Head Gasket Set for a 3.0 MerCruiser, as well as MerCruiser Gasket Sets for Engine Overhaul and Oil Pumps when you want to save thousands restoring your internal engine.

Best of all, we offer fast shipping and the lowest prices for everything else you need to keep your boat in tip-top shape, including Gear Lube Kits, Mercury Drive System Parts, and 100 & 300 Hour Service Kits. 

To help you find the right internal engine parts plus in-depth articles for reference, check out some of our helpful MerCruiser resources:

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

Mercury MerCruiser Internal Engine FAQ

How do I perform internal engine maintenance for my Mercury MerCruiser motor?

Your MerCruiser engine’s internal engine components require regular servicing during the entire lifespan of owning your MerCruiser motor. There are regular maintenance intervals that must be met for Mercury engines, including 20-hour service, every 100 hours, 300 hours, and so forth. 

The following is the Mercury maintenance schedule for 100 hour and 300 hour maintenance intervals (which includes Mercury’s MerCruiser line of outboard, inboards, and sterndrive engines):

100 Hours/1 Year

300 Hours/3 Years

Why should I use Mercury fuel stabilizer for my internal engine components?

Mercury Quikstor treats and stabilizes fuel at every fill-up which is necessary because just about all gasoline today contains up to 10% ethanol. Left untreated, ethanol-blended fuel can break down over time through a process called “phase separation”, leading to gum and varnish build-up. This buildup then leads to blocked fuel flow (in carburetors and fuel injectors especially) and internal engine corrosion due to the moisture content of the water. 

As a preventive measure, fuel stabilizers keep fuel fresh between fill-ups for up to three months. This is also why boaters should use Mercury Quikstor if their boat is stored during winterization (see next section below) or is used infrequently, which can lead to issues with your engine running. 

Before storage, simply add a bottle of Quickstor to your fuel tank, then run the engine so that the treated fuel circulates throughout the engine and fuel lines. This extended fuel stabilizer prevents gum and varnish from forming in the engine, fuel lines, and tank and stabilizes fuel for up to one year, thereby successfully averting any fuel-related problems. One ounce of Quickstor treats five gallons of fuel, so a 12-ounce bottle treats 60 gallons.

Is winterizing my MerCruiser important?

Yes, winterizing your engine is absolutely essential when it comes to preserving your Mercury MerCruiser internal engine components. Properly winterizing your MerCruiser engine should be mandatory for all experienced boaters. Winterizing helps avoid engine damage and will facilitate a smoother start to the beginning of next season - after all, no one wants to wait to get back on the water!

There are several important steps you should take when storing your MerCruiser lower unit to ensure that it’s properly winterized.

1. Flush Your Engine - Thoroughly flush your MerCruiser engine to remove any salt buildup if you are a saltwater boater, or accumulated mud and grime if you are a freshwater boater. Failure to remove this debris from your MerCruiser lower unit leads to corrosion in the engine. And if you’re a saltwater boater, leftover salt crystals in the lower unit can act like sandpaper to your internal engine components.
2. Stabilize Your Fuel System - Fuel starts to go bad within 30 days of sitting in your MerCruiser fuel system. It is vital to use a fuel stabilizer like Mercury Quickstor Fuel Stabilizer when your boat will be sitting unused for more than two or three months. Adding the amount of fuel stabilizer directed on the product’s packaging to your fuel—for instance, 1 ounce of Mercury Quickstor Fuel Stabilizer for every 5 gallons of marine fuel ensures proper winterization for more than 3 months. 
3. Fog Your MerCruiser Engine - Mercury Storage Seal Fogging Oil is a wax-based oil that coats the engine to prevent corrosion.
4. Change Out the Lower Unit Oil - It’s recommended by marine mechanics to change your MerCruiser gear lube before storage to make sure that there is no water in the lower unit’s oil. Any water in the oil could freeze, expand, and crack your lower unit. Additionally, the old oil is more likely to gum up oil passages and corrode components due to changes in its chemical composition through regular use. Last, consult your MerCruiser owners manual for which oil is appropriate for your engine.
5. Disconnect Your Battery - Disconnect your battery and spray CRC Marine Battery Terminal Cleaner on your battery terminals.

Should I use Mercury fuel additives for my MerCruiser’s internal engine components?

Yes, Mercury offers a solid line of Mercury fuel additives that preserve the lifespan of your internal engine components. Here’s what we recommend:

• Quickare treats and stabilizes fuel at every fill-up which is necessary because just about all gasoline today contains up to 10% ethanol. Left untreated, ethanol-blended fuel can break down leading to gum and varnish build-up which causes internal engine corrosion. Fuel additives such as a bottle of Quickare keep fuel fresh between fill-ups for up to three months.
• To clean your engine and fuel system of carbon deposits, add Mercury Quickleen to your fuel tank. Simply add a bottle of Quickleen to your outboard fuel tank once per year to remove carbon deposits, prevent engine knocking, piston seizing, and extend spark plug life. Aggressive fuel system cleaner within Quickleen works to quickly and thoroughly remove carbon deposits from carburetors and fuel injectors, intake valves, spark plugs, piston crowns, and cylinder heads.
• If your boat will be sitting for an extended period of time, you need to add a fuel stabilizer like Mercury Marine Quikstor to prevent both regular and ethanol-blended fuels from breaking down through phase separation, oxidizing, and causing fuel system corrosion, and eventually affecting the engine’s performance. Before storage add a bottle of Quickstor to your fuel tank, then run the engine so that the treated fuel circulates throughout the engine and fuel lines. This extended fuel stabilizer prevents gum and varnish from forming in the engine, fuel lines, and tank and stabilizes fuel for up to one year, thereby successfully averting any fuel-related problems. One ounce of Quickstor treats five gallons of fuel, so a 12-ounce bottle treats 60 gallons.