PS Advisor April 1, 2004 Issue

PS Advisor: 04/01/04

Outboard Flushing
I have just purchased a Suzuki four- horse, four-stroke motor. The manual says that after each use it is important to flush the engine with fresh water after each use in salt water. This makes a lot of sense. However, I keep my small sailboat at a mooring buoy in Puget Sound, and thus have no means of flushing with fresh water each time I return.

How much damage will be done by not flushing? Is there a way I can flush with an improvised gravity feed and a five-gallon bucket?

-Richard Lang
Via e-mail

Manufacturers understandably want their customers to get the best life and performance out of their engines, so outboard engine manuals encourage the user to flush the engine with fresh water after each use, especially after running in salt water. It's definitely a good idea, because aluminum lower units are susceptible to corrosion, and salt can and does scale up in the engine's cooling passages. It's also a good idea to flush if you run in water with a lot of silt or particulates in it.

The trouble is, it really is impractical for many people, and you're a good example. Few who leave their outboard-powered boats on moorings or in slips will haul the boat or the engine during the course of the season with the sole purpose of flushing the engine. It just doesn't happen. People who keep their boats on trailers or storage racks have it easier in this regard, and they're generally more dedicated in their flushing practices.

The standard procedure is to apply a set of flushing "earmuffs" over the cooling-water intakes of the lower unit, screw a garden hose into the muffs, then run fresh water while idling the engine. (Watch that shifter—or better yet, remove the prop for the procedure.) The engine's water pump does the work, so you wouldn't need a gravity feed if you decide to lug a five-gallon jug of water out to the boat, along with a cut off section of garden hose with the male fitting intact.

It's hard to answer your question, "How much damage will be done by not flushing?" because we know of so many outboards that have lived long and useful lives in very salty waters with just a minimum of maintenance, meaning a thorough flushing every once in a while. In northern climes this usually means the end of the season, when the engine is winterized; in warmer waters, maybe once every three or four months.

A good compromise for the mooring- and slip-bound might be to do a good freshwater flush a few times per season, using one of the commercial salt-removers that come in concentrated liquid form. One such is Salt-X (


Outboard Locking
I recently purchased a new inflatable dinghy and six-horsepower four-stroke outboard, and went thereafter to look for a good lock for engine and dinghy. I found little that seemed to me to be exceptionally secure or well-designed, given the parameters of average use and the requirements for mobility.

Is there any commercially available securing system, or combination of systems, which could prevent most thefts?

-Rob Alley
Via e-mail

Actually, the outboard locks that consist of a hollow steel bar or rod that slides over the engine clamps (when they are horizontally aligned) and then padlocked in place are quite effective. Master Lock makes one version, with a high-quality brass padlock operated by a standard key. This is Master part number 162-430D. You can buy it all over the place, but we don't see it listed on Master Lock's website. We've found that the vinyl covering the steel bar eventually gives way and the steel gets a bit rusty. Also, the bar can rattle annoyingly on certain engines at certain speeds.

Fulton Performance makes another version (model OML) that is operated with a barrel key and padded to prevent vibration.

It used to be possible simply to padlock the clamp handles through the holes in their tips with a good brass combination lock, but now that most handles are plastic, that security measure can be overcome with a sharp rap from a hammer.

For engines that are bolted on a transom, there are nut locks like those made by McGard ( or Stazo ( Stazo also has a clever, patented clamp lock called the Smartlock™. See the website, or call Stazo's branch in Thomaston, ME at 207/354-0914.

As for securing the inflatable itself against theft, we have some ideas (involving the use of lifting eyes bolted through the transom) but would like to hear ideas from readers.

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