Frequently Asked Questions

Oil recommendations can be found in the Operation, Maintenance & Warranty manual.  If you have questions on the currently offered Mercury or Quicksilver oils and lubricants, consult with your authorized Mercury dealer or contact Mercury customer service to ensure maximum protection for your outboard.

Inspect gear lubricant for metal particles (lubricant will have a 'metal flake' appearance). Drain lube into a clean pan/container. The presence of fine metal particles (resembling powder) in the gear lube indicates normal wear. The presence of metal chips in the gear lube indicates the need for gear housing disassembly and component inspection by an authorized dealer.

Note color of gear lubricant when draining. If the color is white or cream it MAY indicate the presence of water in lubricant. Gear lubricant which has been drained from a gear case recently in operation will have a yellowish color due to lubricant agitation/aeration. Gear lube which is mixed with assembly lubricant (Special Lube 101 or 2-4-C) will also be creamy white in color. This is normal and should not be confused with the presence of water. If water is suspected to be present in the gearcase, a pressure check of the gearcase should be completed by an authorized dealer. Pouring a portion of the gear lubricant into a glass jar and allowing the lubricant to settle will allow any water in the lube to separate and settle to the bottom of the jar.

The presence of water in gear lubricant indicates the need for inspection by an authorized dealer. The dealer will disassemble the gear housing and inspect the oil seals, seal surfaces, O-rings, water pump gaskets, as well as the gear housing components for damage.

The Operation, Maintenance & Warranty manual outlines the typical maintenance and lubrication items. If your manual is missing or damaged, please order online or through any authorized Mercury dealer. Please have your outboard or sterndrive serial number before placing the order.

For Mercury outboards, the serial number label is located on the transom bracket.

You can locate the MerCruiser serial number label on either the side of the engine or on top of the flame arrester cover.

We do not recommend leaving a lower unit empty during storage periods. An empty oil cavity may allow moisture to collect on the gears, bearings and shafts. Rust will form when the moisture reacts with the air, damaging the internal components.

Note: If water was present when draining the gear oil, the lower unit should be inspected by an authorized dealer.

Click here for tips on winterizing.

The engine oil capacities given in the Operation, Maintenance & Warranty and Service manuals are approximate and indicate what the capacity of the entire lubrication system is. A small amount of oil remains in the crankcase, oil lines, etc. This is why it is difficult to get the indicated amount of oil in the engine without it being overfilled. You should always fill the crankcase according to the dipstick when the engine is level, preferably with the boat at rest in the water. If the oil is at the full mark on the dipstick, then it is at the proper level regardless of how much you put in. It is important not to overfill or under fill the crankcase. The engine oil level should always be between the add and the full marks on the dipstick. 

With time and usage, the engine will sometimes get out of alignment with the transom assembly and sterndrive. For longest engine coupler life, it is important that the engine alignment be as accurate as possible. We recommend using Quicksilver Engine Coupler Spline Grease for proper lubrication. Damage caused by improper engine alignment or lack of lubrication is not covered under the limited warranty.

It is better to change the oil and gear lube at the end of the season, prior to storage. Lubricants naturally accumulate moisture, combustion by-products, and other contaminants during use. It can be detrimental to store an engine or drive with large amounts of these contaminants present.

Mercury High Performance gear lube is recommended for use in all sterndrives.