EFI single throttle-body four-stroke outboards (like the Yamaha F200 and F175), require a slightly different fogging and winterizing procedure than many other types of outboards. Unlike carbureted engines you can’t simply spray fogging fluid in via the air intake, because the oil is too thick to effectively make its way through the fuel system. Historically, that might mean removing the spark plugs and spraying the fluid directly into the cylinders. This, however, can result in hydro-lock. The answer is to be found by adding a specialized fogging fluid to a remote fuel supply, and running it directly through the outboard engine. Here’s how it works:


This is the process recommended on Yamaha’s Maintenance Matters site, which, by the way, has reams of excellent outboard care and maintenance information. But just to be sure, we contacted our insider connections at Yamaha and confirmed that this is the very best way to fog a motor like the F175. What if you have a different type of outboard engine? Or, if you have an inboard or stern-drive boat? No worries—we’ve got you covered, too. Check out these articles and videos, to learn the proper process.

Wait a sec, folks. Don’t move on just because you’re done learning about winterizing. We have a lot more outboard care and maintenance tips in store for you. If you want to learn more, be sure to watch:

Written by: Lenny Rudow
With over two decades of experience in marine journalism, Lenny Rudow has contributed to publications including YachtWorld, boats.com, Boating Magazine, Marlin Magazine, Boating World, Saltwater Sportsman, Texas Fish & Game, and many others. Lenny is a graduate of the Westlawn School of Yacht Design, and he has won numerous BWI and OWAA writing awards.