Is fogging important for winter storage?

Joined
Aug 10, 2019
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56
Location
Downeast, USA
Hi - I’ve got a new 90hp Mercury on my boat. First winter storage. Is fogging important for winter storage? I’ve never done it with smaller motors. I’m in the northeast and the boat will sit wrapped outside Nov-Apr.

Thanks for your advice!
 
I don't generally do it, but if I did, I'd run it out of gas, then throw a small amount of stabilized 2-stroke gas & oil in, and run that through. Not so much for what it does for the cylinders, but it'll help the carburetor and fuel system.
 
I bought fogging oil for my ope years ago. Used it a few times, not since. No issues.

I’d be more concerned with running it dry if I could. Thst said, my gasoline vehicles have on occasion sat the winter, or longer, even years, with the same gas.
 
For the short time I owned an OB 150 Yamaha I pulled the plugs and sprayed each cylinder. It was the least I could do after having a life of winterizing stern drives....
 
Probably the answer is "could be". If your motor stays dry in low humidity, probably not needed. If it gets damp(hole in the plastic) then it might save some internal rust?
 
My opinion is fogging oil is only helpful for storage over 1 year. Seasonal storage is no problem at all without it. The only time I was glad I fogged an engine was a snowblower I had in storage for a couple years. I moved into an apartment before buying another house.
 
For five decades of boating I always properly winterized the engines

With outboards I used fogging fluid and inboard/outboards of the last two decades or more. I pour oil in the carburetor while the engine is running and smoke it up while I have the water intake sucking in antifreeze before shutting it down
 
With a carb some try to spray oil at a fast enough rate to stall the engine. Others will pull plugs and spray in some fogging oil. Fogging oil has a sticky component so it it clings to the piston and cylinder walls rather than pooling at the lowest point. With several cylinders one or two are bound to have valves open to the atmosphere.

If you have fogged you should start the engine then change the plugs.

The owner's manuals I have read say instead to prepare a small container of a fuel mix. Fuel & 2 cycle oil & stabilizer. Run all of that through the engine. For a 4 cycle engine.
 
How I fog an I/O (Mercruiser/Volvo Penta) large displacement engines - only ever owned V8's

Bride at helm, boat on muffs.
Warm engine until thermostat opens
Run boat at idle, spark arrestor removed
Spray down each barrel with two cans, or two cans into the throttle body until engine starts to stumble
Ask bride to turn it off - keep spraying until engine dies
Turn master kill switch OFF
Open throttle to full
Ask bride to crank engine, spray both bottles for 5 seconds while cranking
Stop cranking, drain block and exhaust manifolds - be sure to poke out the drain holes
Put lugs back in
Pull large radiator hose and fill block with coolant

That is about it...not including the oil change. Although this is MUCH easier with a closed cooling system.
This method has always worked for me, and keeps me from pulling the plugs.
 
For my two stroke 115 Yamaha, I remove the spark plugs, turn one piston to farthest away for max volume, spray the fogging solution, turn the motor by hand and repeat with each cylinder. I then replace the plugs and that’s it. It’s 30 years old and runs great. Maybe I’d get the same results by saying a chant. Who knows.
 
I am not sure fogging is really worth it. I have never looked in the spring to see if all the fogged cylinders were rust free in the spring. One or two likely had valves open and so outside air was getting into the cylinder. Will that cause rust? The rust is likely removed when the engine is started in the spring.
 
My opinion is fogging oil is only helpful for storage over 1 year. Seasonal storage is no problem at all without it. The only time I was glad I fogged an engine was a snowblower I had in storage for a couple years. I moved into an apartment before buying another house.
100% agree with Brandon.
 
Stabil in fuel and ran until the mix is in the fuel system at-on the engine. Boats stored in coastal areas are exposed to more corrosion. Inland boats stored probably don’t benefit from fogging unless the downtime is more than a year.
 
While Indo not have a boat, I do have snowmobiles and several other pieces of OPE.

As stated before, I think your location has a lot to do with the need to fog. I live on the prairies and while it rains and snows, we do not get the humidity that the coast gets.

I do not fog anything. Never have and likely never will. The only times I have ever encountered rust in cylinders was when the head(s) were pulled, leaving it exposed. As an example, there was this old dilapidated auger at my old acreage. It had a Wisconsin single cylinder with the carb ripped off. It sat like that in the elements for decades before we got rid of it. You could freely spin it over with your hand on the recoil. That's one example of many.

Out here I think your are better served ensuring your batteries are charged and fuel treated.
 
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