MARINE GREASE
Greases are semisolid lubricants possessing a high initial viscosity. Upon the application of sliding pressure — known to engineering types as shear — the viscosity drops to that of the base oil used in the grease. Grease is used as a generic term, and while the old saw that “any grease is better than no grease” usually proves true, there are specific formulations that will serve the lubrication needs of your boat’s engines, trailer and accessories better than others. Here are some points to ponder prior to purchasing grease for specific applications. —Kevin Falvey
SNAPS AND ZIPPERS
You don’t want dark red, green or blue smears on your boat’s canvas, yet you need the snaps and zippers to work well. Lubes made with Teflon or Star brite’s PTEF lubricant work well (as an aside, so does rubbing a candle or crayon).
BATTERY TERMINALS
The grease used on battery terminals should be a high-temperature silicon or Teflon base. Battery terminal connections can get hot enough to liquefy some greases (making “old reliable” Vaseline a bad choice). Liquefied grease may run in between the connections and create an insulating barrier, diminishing electrical output.
SPARK PLUGS
Dielectric grease is silicone-based, nonconductive, protects electrical connections, will not break down most rubber or plastics, and withstands high temperatures. Apply it on the spark-plug boot to create a waterproof seal rather than on the spark-plug terminal itself. Trailer connectors can be treated the same way with no shorting.
SPLINES/LINKAGES
White lithium-based greases include zinc so it’s easy to see if the grease is in place. It’s heat-resistant and stays put, resisting running, sliding or being flung off. Use white lithium-based grease for sterndrive coupler splines, gimbal bearings, throttle linkages, prop shafts and other applications.
THREADS
Anti-seize lubricant helps prevent seizing and galling (“cold welding”),
and makes removal of fasteners, spark plugs and drain plugs easier. For marine use, purchase anti-seize that uses nonmetallic fillers.
STEERING COMPONENTS
A lithium wheelbearing grease serves fine for lubricating steering-system tilt tubes, support arms and more. Be sure to clean old grease, which turns hard and contains contaminants, from steering mechanisms annually.
Boattrailer wheel-bearing grease needs to withstand heat and high-rotational speed, and also repel water. Its resistance to “washout” is what differentiates marine wheel-bearing grease from automotive
WHEEL BEARINGS
wheel-bearing grease. This is also a good general-purpose grease that can serve well in many applications, if the ideal lubricant is unavailable.