Winterizing EFI Stern Drive Engines


Several weeks ago we published a article by our favorite boatyard owner, Paul Esterle, and received lots of mail complaining that Paul forgot to discuss winterizing EFI stern drive engines. All we can say is that being a boatyard owner is never a victimless crime. This week Paul gives us his take on winterizing and most of it comes right out of a MerCruiser service bulletin.


Winterizing EFI
To fog or not to fog, that is the question: whether ‘tis nobler in the mind to suffer the slings and arrows of outrageous fortune, or winterize against a sea of troubles...

Winterizing a Fuel Injected I/O Sterndrive Engine

By Paul Esterle

Most winterizing articles simply state “fog the engine’. This is true for carbureted engines but a different technique is used on fuel injected engines. To properly protect the internal engine components from rust and corrosion, you still need to run an oil-rich mixture through the engine; you just do it a little differently. This information was gleaned from a MerCruiser service bulletin.

Step #1:To start, you mix one quart of Mercury 2-cycle outboard oil with 2-1/2 gallons of gas. Add about 2 to 3 ounces of fuel stabilizer and mix well.

Step #2: Remove your fuel water separator canister and replace with a new one. Before screwing the new canister in place, fill it with the gas/oil mixture.

Step #3: Disconnect the fuel line from the tank and place it in the gas can with the oil/gas/stabilizer mix.

Step #4: If the boat is hauled out, attach muffs to the lower unit using antifreeze.

Step #5: Start and run the engine until you’ve emptied the gas can. Run the antifreeze through the engine at the same time. You should have reached the engine’s operating temperature, the thermostat should be open, and the pink stuff should have circulated nicely in the block. Remember to use -60 or -100 marine antifreeze, it has corrosion inhibitors that the -50 pink stuff doesn’t have. Don’t use automotive antifreeze -- it is poison to pets and wildlife [to say nothing of people, and CSI folks say it is hard to detect in autopsies.—Ed.] Store the stern drive in it’s down position to avoid permanently deforming the rubber transom boot.

Step #6: Book a winter getaway in someplace warm.

--Article courtesy of Paul Esterle, author of “Maintain and Improve your Powerboat” published recently by McGraw-Hill. Visit Paul’s website thevirtualboatyard.com for helpful tips all year long.