How Long Will a Fogged Outboard Last in Storage?

This is the time of year that people start thinking about pulling their boats and winterizing them. Part of that routine is the so-called fogging of outboard engines, which is the process of injecting oil into the carburetor and cylinder(s) so that the engine won’t rust during storage, particularly if it is subject to wide temperature changes causing internal condensation. My question is, just how long is this storage technique good for?

Spraying fogging oil into the engine's carb and cylinders prevents corrosion -- but for how long?
Spraying fogging oil into the engine’s carb and cylinders prevents corrosion — but for how long?

Five years ago, I was in search of a small outboard engine. A friend, Ed, had a 5-hp Honda 4-stroke from the early 1990s that he was willing to sell because he had just bought a new, lighter 3-hp Mercury 2-stroke for his inflatable. The Honda wasn’t running.  We didn’t know what was wrong, what it was worth, or how much it might cost to fix it, so before buying it I agreed to have it looked at by a certified Honda dealer–I took it to the Boat Guy Inc. on Cape Cod for evaluation.

It turns out the Honda ran beautifully after the rust was cleaned out of its fuel filter. However, the old metal external tank was scaling badly and needed replacing.  I was told the engine was worth around $400, but it would need a new $180 tank and hose!

At that point, something surprising happened. The owner of the Boat Guy Inc., Andy Bancroft, an old acquaintance from my yacht yard operation days, approached me about buying the Honda outright. He explained that he collected old engines, that this was a missing piece to his collection, and said it would look dandy in his showroom lineup.

After telling him I really wanted an outboard kicker with a long shaft to push my project boat while I was searching for a replacement diesel, he smiled and said he had just the thing — a 2004 Mercury 6-hp 4-stroke long-shaft, replete with new tank and hose. It had been serviced, and was currently winterized and fogged out. I agreed to pay my buddy Ed $200 for his Honda (given that it would need a new tank) and then swapped it for the newer long-shaft Mercury. Everyone seemed happy with the deal.

Now the question comes. How long will a winterized, fogged-out engine last? You see, I got rid of the project boat after a tree limb damaged the mast last year, and I still have the Mercury in my nice warm basement. Truth be told, I have never run it, being reluctant to “unwinterize” it if I wasn’t ready to use it regularly. Oh, I’ve thought about selling it too, but I know I’ll need to demonstrate that it runs to any prospective buyer. I’ve got a barrel ready to test it in, and know I should satisfy myself that it runs. I have rolled it over a few times.  I’m not sure who is more foggy on when to proceed — me on when to pull the starter handle, or the engine residing in a state of pure fogged-out stasis.

Eds’ note: If anyone out there has experience storing outboards over multiple seasons, tell us about it in the Comments section. 

Preseason Outboard Maintenance

Seaswirl 2301
50 percent of engine problems could be avoided by annual preventative maintenance on your outboard.

In early May, I asked my buddy Lee if he had launched his 2005 24 foot Seaswirl with its 250 hp Yamaha outboard yet.

“Not yet,” said Lee. “I’m bringing it in to have the engine serviced this weekend, then weather permitting, it’ll go in next week. I don’t want to have any problems once the season starts.”

I’m pleased and surprised by this reasonable approach to preventive maintenance, since I’ve known Lee for over twenty years and always thought he was rough on his vehicles.

So I asked him what the service entailed.

“They change the oil, fuel filter, and spark plugs, and every two years they swap out the water pump,” said Lee. “They go through it with the computer diagnostic, check the throttle and shift cables, and lube and grease everything. Why are you so  interested?”

I confessed: I wanted to write about it.  And since I have always been a proponent of preventive maintenance, I was wondering what the Yamaha authorized service covered and how much it cost.

“It’s a couple hundred bucks, but I can tell you it costs a lot less than one tow service would,” Lee said.Yamaha outboard

I believe him, since I know he had to use a tow service when he went aground and ripped the lower unit off the engine last season… but that’s another story.

I think Lee is on the right track, and that having preseason preventative service by an authorized service tech on your outboard is good advice. It should give him peace of mind, the confidence to push his boat during many offshore fishing trips, and a season of uninterrupted, hassle-free use – that’s worth every penny.

How to Salvage (Pickle) an Outboard

The review team over at has willingly sent a perfectly good outboard engine swimming, just to show you how to get it running again. Enjoy!

If you have ever dropped an outboard engine overboard, had one jump off the transom, or had your boat sink in the slip, then you were in a pickle. In fact, you needed to “pickle” it to salvage that poor powerplant.

Haven’t faced this problem just yet? Good. We’re certainly not suggesting you try this intentionally, as we did. But you should know exactly how this process works ahead of time – because if your outboard does take a saltwater submersion, time becomes imperative.

Read the rest of How to Salvage (Pickle) an Outboard.

Outboard Performance: Upgrade Your Propeller

stainless outboard propeller
Upgrading your outboard to a stainless steel propeller may be a smart choice, but make sure the material the prop is made from does not conflict with the hull material.

Changing the prop on your outboard may be the least expensive yet dramatic way to fine tune and customize your boat’s performance for your use.  There are plenty of websites with prop calculators that will take the size and weight of your boat, along with your engine, current propeller, and current performance data, then recommend a replacement prop based on your desires for improvement in a particular area. Say you want better fuel efficiency, or better top-end speed; maybe you use the boat for fishing offshore in rough water or water skiing with the whole family onboard and want to customize it for that—all without buying a new engine or different boat. What’s behind their recommendations, and how does the calculator work? The answer, in a word, is compromise.

You can change the prop and get a better “hole shot” for water skiing, but it will more than likely require a compromise in top-end speed, for instance. Engine manufacturers have likely installed a general-purpose prop that meets the recommended operating range your outboard was designed for. The operator’s manual will express this as a certain horsepower at a certain rpm (revolutions per minute). But what they can’t know is how you typically load your boat, what you’ll primarily use it for, and the conditions you normally encounter. This is where changing the prop may fine-tune your boat to make a huge difference to you.

Maybe the boat’s prior owner had his own uses in mind when he swapped props, and these conflict with how you intend to use the boat. The goal in prop selection is to determine what propeller style and size will maximize performance for your boat, while allowing your engine to operate in the recommended rpm range.

Before rushing out to buy a new prop, establish a current performance baseline:

  • Look up the engine’s operating range in the operator’s manual and make special note of the top end of that range.
  • Take the boat out for a test ride the way you would normally use it (weight and trim) and note the rpm at wide-open throttle (WOT) and what optimal speed you attain (you may have to adjust engine angle trim). If you do exceed max rpm, throttle back to recommended limits.
  • It will also be helpful to know how much fuel you burn per hour at your normal cruising speed.
  • Now find out what prop you have, and what material it’s made of.Propeller Pitch

Props are usually stamped with their diameter and pitch on the hub. The diameter number comes first and the pitch next.  Pitch is defined as the distance the propeller would move through a solid material in one complete revolution, with no allowance for slippage. In other words, a propeller with a 21-inch pitch would screw 21 inches into the material in one turn. (If there were zero slippage involved in the watery medium of boats, a boat would therefore move forward 21 inches, too. But of course there is slippage.)


Outboard props come in a variety of materials, from plastic on smaller engines to aluminum, composites, and stainless steel on higher-end props. You may be able to increase performance by simply getting a higher-end material like stainless that won’t flex as much. Also, because  it’s stronger it may have thinner blades and be more efficient.

Number of Blades

Generally speaking, more blades are more efficient at moving water and give you more power, but will have more drag and be less fuel efficient at higher speeds. More blades will allow your boat to stay on plane at lower rpm.


Diameter and pitch are the main design characteristics, but there are many other subtle design elements such as cup and rake.  Cup is the small radius of curvature located on the trailing edge of the blade. This curved lip on the propeller allows it to get a better bite on the water. This results in reduced ventilation, slipping, and allows for a better hole shot in many cases. Rake is the degree the blades slant forward or backward in relation to the hub. Rake can affect the flow of water through the propeller. Aft rake helps to trim the bow of the boat upward, which often results in less wetted surface area and therefore higher top-end speed. Forward, or negative rake, helps hold the bow of the boat down. For a more detailed description of design elements and propeller definitions click here.

Just looking at the prop won’t tell you the exact details of the subtler design elements, and to know these quantitatively you may have to have your prop analyzed by a pro like H&H Propeller with the right equipment and software to measure these subtleties.

If your test ride results in over-revving the engine, you’ll need to increase the pitch of the propeller. Increasing the pitch increment by one inch will result in approximately a 200-rpm drop. Keep going until you are within the rpm limits of the manufacturer. If your test run results in a lower-than-maximum rpm rating given in your engine’s operator manual, you may need to decrease pitch — decreasing pitch will increase your rpm.

For every inch of change in pitch, the effect will be approximately 200 rpm. If you are going to employ the subtler design elements such as switching from an uncupped to a cupped propeller, which will also reduce your rpm—I recommend you talk to a pro about these nuances. A cupped propeller of the same pitch and diameter will typically reduce your rpm by approximately 200.

If you use your boat for multiple activities like fishing, cruising, and skiing, one prop probably won’t do all these things equally well. Remember, the compromise was to choose the best prop for a given set of circumstances, and it may be that multiple priorities will require more than one propeller — one for each specialty and all staying within the rpm limits of the engine. Once you know about your engine’s limits, current boat characteristics, use priorities, and current prop, you’ll be able to choose your next prop wisely—even if it means a little compromise on the way.

Inboard or Outboard? The Boat You’ll Buy Next

You’re in the market for a new boat, you know where you’re going to keep it so you know the general size and draft constraints.  You’ve thought about how you will primarily use the boat—now you’re down to the final details before you buy.  What are your preferences for powering the boat, inboard or outboard power?

Inboards are reliable, and most maintenance can be done by the owner‚ though access may be tricky. Doug Logan photo.
Inboards are reliable and most maintenance can be done by the owner‚ though access may be tricky. Doug Logan photo.

Clearly, from 30-40 feet and up, inboards are the choice.  A boat that size needs an inboard because of its deeper draft and electrical requirements.  Below 30 feet, particularly if you have draft limitations or expect to keep the boat on a trailer, outboards are a good choice.  Also, if you plan to go gunk-holing or would like to drive the boat up on a beach, kicking up the engine is a nice option. The only time that inboards are good in shallow draft situations is when you have jet drives.

So size, draft requirements, and what you plan to do with the boat are some of the considerations in your decision, but you still aren’t sure.  What else should you consider?

One big difference is fuel type.  Outboards run on gas; inboards are predominately diesel-powered. Oh, you can find gas inboards, but for safety reasons I would go with a diesel inboard every time.  (Two exceptions for a gas inboard would be if you are considering a power-driven Formula-type race boat for performance reasons, or an older used boat because it is cheaper.)

Outboards are easy to replace, and new models like this Yamaha VMAX are quiet and environmentally friendly.
Outboards are easy to replace, and new models like this Yamaha VMAX are quiet and environmentally friendly.

Another consideration is power and torque vs. speed. Power and torque are two strengths of diesel inboards. And while there are some very fast turbo-diesel inboard boats, speed is generally the domain of gas outboards.

Finally, there are maintenance, dependability, and cost issues.  A few years ago, I would’ve said that diesel inboards were more likely to be yard-maintained by a professional mechanic and hence would be more costly to own than an outboard; with today’s sophisticated outboards, that is almost reversed.  Simple diesels are easy to work on and very dependable, even if you have to be a contortionist to shoe-horn yourself around a tight engine compartment. Modern computer-controlled outboards—particularly the large ones— need technicians with the right training and tools to work on them.

If you do have to replace or upgrade an engine or prop, it is easier with an outboard.  And on a smaller boat, having outboards will give you more space for you and your guests.

Editor’s Note: To help with your next decision, read Do You Need a Surveyor?