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

Discussion in 'Engines and Propulsion' started by bgstar19, Jan 9, 2019. Add this thread to a FAQ

  1. bgstar19


    Joined Jul 25, 2018
    20 posts, 2 likes
    O'day 19 MK-II Weekender
    US 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?

  2. Don S/V ILLusion

    Don S/V ILLusion

    Joined Sep 25, 2008
    5,235 posts, 404 likes
    Alden 50
    US Sarasota, Florida
    I never did that and never had a problem. It doesn't hurt to fog the engine but I suspect it's one of those "feel good" things

    Captain Larry-DH and Parsons like this.
  3. LakeShark


    Joined Sep 15, 2016
    368 posts, 129 likes
    Catalina 22
    US 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 ;).

    Meriachee and Will Gilmore like this.
  4. Parsons


    Joined Jul 12, 2011
    669 posts, 257 likes
    Catalina 36
    US Bay City, MI
    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.

    Will Gilmore likes this.
  5. Rich Stidger

    Rich Stidger

    Joined Feb 10, 2004
    2,844 posts, 283 likes
    Hunter 40.5
    US 1997 h40.5 Bristol, 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.

  6. kloudie1


    Joined Nov 6, 2006
    8,184 posts, 687 likes
    Hunter 34
    US 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.

  7. Justin_NSA


    Joined Jul 7, 2004
    5,147 posts, 963 likes
    Hunter 30T
    US 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:

    justsomeguy and kloudie1 like this.
  8. shemandr


    Joined Jan 1, 2006
    3,798 posts, 783 likes
    Marblehead Skiff 14'
    US Greenport, NY
    I might put a little Marvel Mystery Oil in the spark plug holes and pull the cord a few times.

    Captain Larry-DH likes this.
  9. Captain Larry-DH

    Captain Larry-DH

    Joined Jun 14, 2010
    544 posts, 239 likes
    Quorning Dragonfly 1200
    US home
    Any oil would do. Also, pull the starter cord slowly until you feel strongest resistance. At that point your valves are closed.

  10. jon hansen

    jon hansen

    Joined May 25, 2012
    1,249 posts, 710 likes
    john alden caravelle 42
    us 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

    Will Gilmore likes this.
  11. Will Gilmore

    Will Gilmore

    Joined Oct 19, 2017
    3,902 posts, 1,912 likes
    O'Day 19
    US Littleton, NH
    Wow, so much to learn here. And who says powerboaters simply push a button and go.

    -Will (Dragonfly)

  12. thinwater


    Joined Mar 26, 2011
    2,172 posts, 490 likes
    Corsair F-24 MK I
    US 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.

  13. Gunni


    Joined Mar 16, 2010
    5,685 posts, 1,348 likes
    Beneteau 411 Oceanis
    US Annapolis
    Why do you think there are so many of those decades old 2-strokes laying about. They fog themselves every minute they run - hard to kill.

    RussC, jon hansen and Parsons like this.
  14. Parsons


    Joined Jul 12, 2011
    669 posts, 257 likes
    Catalina 36
    US Bay City, MI
    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.

  15. Gunni


    Joined Mar 16, 2010
    5,685 posts, 1,348 likes
    Beneteau 411 Oceanis
    US Annapolis
    As the former operator of an old race RZ350 yamaha rice burner - change to synthetic oil mix.

    RussC likes this.
  16. FDL S2

    FDL S2

    Joined Jun 29, 2014
    255 posts, 115 likes
    S2 7.3
    US Fond du Lac
    I have an RD350 (and always wanted an RZ) agree synthetic performs better.

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