Boat yards winterize lots of boats in just a few weeks, so for tips to quickly store outboard engines, we went to Thurston’s Marina (thurstonsmarina.com) on Lake Winnipesaukee where they prep 150 outboards each fall against New Hampshire’s brutal winters.
1) To start, add fuel stabilizer, top off tanks, and run the engine in fresh water for about 10 minutes. “With the green STA-BIL, it’s easy to see when the additive makes it through all the fuel lines to the fuel filter,” says Assistant Service Manager Nicholas Thurston.
2) Thurston then connects a 3-gallon tank directly to the motor with his winter storage blend — 50 percent gasoline with fuel stabilizer, 40 percent fogging oil plus a bit of 2-stroke oil and gas-line antifreeze — that protects the fuel system and fogs the motor in 5 minutes running time.
3) If he uses traditional fogging oil rather than his storage blend, on a four-stroke outboard Thurston disconnects the hose that carries oily air from atop the cylinder head back to the engine air intake so he can spray fogging oil into the Positive Crankcase Ventilation valve. It’s quicker than removing all spark plugs to spray oil into each cylinder, and it lubes intake valves and seats. With the engine running, spray for about 45 seconds. Fog two-stroke outboards by spraying into carburetors or into each spark plug hole.
4) On the lower unit, pull the lower drain plug and check for cloudy, milky or emulsified oil. That indicates it’s mixed with water which will either freeze and crack the lower unit or pit and ruin steel bearings.
5) “As long as the engine is left vertical, the water will drain out, so there’s no need to run nontoxic antifreeze through the cooling system.,” Thurston says. His yard stores boats on racks, but trailered boats might require digging a hole to drop the prop and skeg into at the stern of the boat.
Tip: A bit of fogging oil or winterizing mix might drip out the exhaust over the winter, so put a scrap of cardboard beneath outboards stored over concrete.
Advice for Saltwater Boaters
“Flush the engine with freshwater for 20 minutes, then run Salt Away through to eat up any remaining salt” says Jim Patnaude who owns HHB Marine on New Hampshire’s seacoast. “Grease all the fittings on the tilt assembly, and take the cowling off and spray the entire engine with WD-40 to ward off corrosion on surfaces coated by salt air.”