Forgot to fog my outboard, what's the worst that can happen?

Jul 25, 2018
43
O'day 19 MK-II Weekender Narragansett Bay
I forgot to fog my 5 hp 2-stroke Mercury outboard motor when I put it away for winter storage, what's the worst that can happen?
 
Sep 15, 2016
790
Catalina 22 Minnesota
The worst thing is that your motor will be seized and you'll need a new one.

The best case is nothing will happen

The most likely thing is that it will smoke a bit on restart in the spring and you may have to deal with some old gas in the carb which is easily drained and cleaned with an external spray. It's really not that big of a deal. After All I rarely fog my lawnmower and it seems to keep running. I am sure it will survive the larger question is did you get the water out of it ;).
 
Jul 12, 2011
1,165
Leopard 40 Jupiter, Florida
Worst-case, and highly unlikely: Rust in the cylinder. The 'fogging' is inside the cylinder, so the gas / carburetor comment is not relevant. I hope that you did use a fuel stabilizer in the last tank of gas because gasoline will begin to separate and 'gum' after a month or so. With stabilizer, you can add years to the mixture (according to manufacturer's advertising). You have much less chance of getting rust in your cylinder with a two-stroke because of the 1:50 oil mixture that you have in there. I've left two-stroke motors for months without fogging, and upon disassembly they showed no signs of corrosion. You're probably fine.
 
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Feb 10, 2004
3,917
Hunter 40.5 Warwick, RI
Be sure to store your outboard upright. I once had residual water run into the power head totally destroying the engine. This disaster was enabled by a failed seal, but there was no indication of that failed seal.
So I always store upright. And I fog the cylinder and run fuel stabilizer in the E0 gasoline. Belt & suspenders approach.
 
Nov 6, 2006
9,884
Hunter 34 Mandeville Louisiana
I agree, fogging seems like a good thing and it is if the engine will not be used for a few years.. not going to hurt it for one winter, especially if you use a good quality two stroke oil..
I recently had a weed eater two stroke that went under water (fresh) for several hours and three months later I tried to crank it and would not budge.. removed plug and found it hydrolocked.. drained it and found it was free.. put in gasoline and it fired right up.. Good synthetic two stroke oil.
 
Jul 7, 2004
8,402
Hunter 30T Cheney, KS
You are guilting me. I have a 14hp generator in my garage I haven't turned over in years!
If you ever want to prevent a power outage from happening, buy a generator!:frown:
 
Jun 14, 2010
2,081
Robertson & Caine 2017 Leopard 40 CT
I might put a little Marvel Mystery Oil in the spark plug holes and pull the cord a few times.
Any oil would do. Also, pull the starter cord slowly until you feel strongest resistance. At that point your valves are closed.
 
May 25, 2012
4,333
john alden caravelle 42 sturgeon bay, wis
dino oil spreads over surfaces while stored - GOOD
synthetic oil creeps off the surfaces while stored - BAD
long term storage using marvel mystery oil not good, it drys and cakes. MORE BAD
fogging oil spreads and clings to metal surfaces GOOD
for winter storage i get engine up to full operating temps, disconnect fuel so to run engine totally out of fuel.
stable fuel preservative has always worked for me for up to a year. thats in tanks before storage and when shutting off engine at full operating temps to run out fuel if one can.
alot of storage is the damm wimpy gas changing to varnish.
pulling through engine to oil after long sitting could harm dry rubber impeller.

so with those thoughts. i do fog the 454 rat block in my formula day launch cause it is so easy and has no fuel cutoff valve. i do not fog my outboards as the are to hard to do without a mess. i run dino oil in my two strokes. i do fog all my rc airplane engines cause it's easy and the fuel is alcohol with then attracts moister.
the WD in WD40 stands for water displacement.
these are my personal views on such, take it for what you paid for it.

my guess, you'll be fine.
i do not fog my diesel on the alden
 
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Oct 19, 2017
7,732
O'Day 19 Littleton, NH
Wow, so much to learn here. And who says powerboaters simply push a button and go.

-Will (Dragonfly)
 
Mar 26, 2011
3,400
Corsair F-24 MK I Deale, MD
In 30 years, I've never fogged an engine, drained a carb, or run an engine dry, and I've always used e10. I do use Boibor EB, which has tested best among anti-corrosion additives. The engines have always died at >20 years due to general corrosion (salt water) and ignition problems. Just not reliable enough, through probably fixable.

Last time I was out (last week--January temperatures) the motor started first pull each time. A minute of choke, then throttle down and go. The reason is that I try to sail at least once each month. I'll at least run the engine under load for while, if there is too much ice to go out, which is rare in saltwater.

Yes, 2-strokes have more oil on the plug, but I'm not sure I understand why the cylinder wall and bearing lubrication would be better for storage.

If I were concerned I would pull the engine over one turn each month.
 
Jul 12, 2011
1,165
Leopard 40 Jupiter, Florida
True for Rust, Gunni. I have found that the gumming from un-treated gas with the 2-stroke oil mix is terrible, however. Gotta stabilize.
 

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
I have found that the gumming from un-treated gas with the 2-stroke oil mix is terrible
As the former operator of an old race RZ350 yamaha rice burner - change to synthetic oil mix.
 
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