PS Advisor July 2014 Issue

Winterizing an Outboard

What’s the best procedure for storing a small engine?

For winterizing a small outboard engine, is it best to run the gas out of the engine or store it full with an additive mixed in? Is it the same for two-stroke and four-stroke engines? What about ethanol and non-ethanol gasoline?

Via email

Those are good questions, as outboard (OB) engine manuals are often contradicting as to what’s the best practice for seasonal storage.

According to David Meeler, Yamaha’s marine product information manager, Yamaha advises OB owners to treat the fuel (ethanol and non-ethanol) with a stabilizer and conditioner, and then run the engine for a sufficient time to allow the treated fuel to pass through the entire fuel system prior to storage. Yamaha recommends that fuel tanks be stored nearly full (7/8 full) to minimize the available area for condensation, yet provide space necessary for thermal expansion and contraction.

Some other manufacturers say to remove or use as much fuel as possible from the tank, and let the engine run until it dies, effectively clearing the carburetor. However, in practice, this often gets the carb only 70 to 90 percent dry, and whatever remains will turn into goo. So, if the outboard will be stored for a month or less, which is better?

Our rule of thumb is that if the engine will be out of commission for six months or more, run it dry. But if it’ll be stored for only a few weeks or a month, leave it be. Two-stroke engines tend to be more forgiving than four-strokes, but the rules are the same.

Regarding an external tank, keep it full; that is what boat yards require (fire hazard). This also will minimize tank breathing, water absorption, and oxidation. Tanks fitted with silica-gel vent filters do very well; the adsorbent effectively reduces water entry, fuel evaporation, and oxidation (see PS February 2013 online). One exception to the “keep-it-full” rule is portable gas tanks, which should be drained and left dry.

Non-ethanol gas evaporates less, draws less water, is less corrosive, and is less prone to gum than ethanol blends, but the same precautions apply. We’ve tested additives, and though initially skeptical, found some that are really worth the money (see PS August 2012 online). Be sure to use a stabilizer with ethanol gas blends (see PS November 2008 online).

Manson Supreme anchor
Photos by Evans Starzinger and courtesy of Gerry Hutchins

Anchor Upgrade

I am considering upgrading from a 44-pound Lewmar Delta plow to a 60-pound, galvanized Manson Supreme anchor on my 41-foot catamaran for more of a storm anchor-type setup. Do you recommend a swivel-type connection between the chain rode and the anchor?

Tom Welch
Going Nowhere, 41-foot MaineCat
Clinton, Conn.

We don’t recommend connector swivels for anchor rodes, but this has been the subject of long-standing debate. (In fact, Lewmar recommends using anchor swivels.)

In our opinion, they are not necessary in an anchor rode. In a mooring setup, the large-diameter chain allows for much larger swivels, but an anchor rode’s smaller diameter often calls for undersized swivels. Eliminating the swivel in an anchor rode eliminates the weakest link. (See PS Advisor, May 2010, and Mailport, January 2011 online.)

Our concerns over swivels—especially stainless ones—stems from frequent inconsistencies in the materials and manufacturing processes and the fact that stainless can fail without warning. We prefer properly seized D-shackles or pin shackles for chain-to-anchor connections. If you do use a swivel, Mike Muessel, the mooring installer for Oldport Marine Services in Newport, R.I., recommended hot-galvanized swivels from Chicago Hardware (

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