Fogging oil

[brian4321]

How important is it and what do you guys do? I have a 2000 5.0 mercruiser and the first few years i would spray fogging oil down the carb till it choked out and last year I poured sea foam in till it choked out...do you guys fog ur engines while winterizing? If so how do you do it? My boat will be sitting for approximately 4 months

 

[frantically relaxing]

Never fogged an engine. IMO totally unnecessary.

 

[alldodge]

I don't fog my MPI but do fog my carb motor. Your doing your motor wrong by using seafoam, IMO your washing all the oil off the cylinder walls. I would suggest fogging oil or another spray type oil, even silicone oil

 

[Watermann]

Yeah Seafoam has a purpose and that's not it. If you want a product that works better than Seafoam get some QS Power tune. Four months isn't really long term storage to me and all the internals should have a coating of motor oil on them. I can't say I've ever read a thread about "Whoa is me, I didn't fog my motor and now it's junk". More common is the whoa is me I didn't winterize my IO properly and now the motor is cracked up junk.

 

[roffey]

to be honest I don't use stabilizer or fog the motor but I could be totally doing it wrong.

 

[brian4321]

Thanks for the advice guys, no more seafoam to "fog" the motor.. most of my fellow boaters don't fog their engines and I was considering not doing it this year...not that it's a big hassle or anything but thought if it's not necessary I'll skip that step

 

[lckstckn2smknbrls]

I pull the spark plugs and spray fogging oil into the cylinders. Then put the plugs back in.

 

[Blind Date]

I fog but I've often wondered if it is really necessary. After reading some of the responses I think I'll skip it this fall and probably going forward. Do guys with classic cars bother fogging the engine when they park them for the winter? I don't think they do.

 

[wrvond]

How important is it and what do you guys do? I have a 2000 5.0 mercruiser and the first few years i would spray fogging oil down the carb till it choked out and last year I poured sea foam in till it choked out...do you guys fog ur engines while winterizing? If so how do you do it? My boat will be sitting for approximately 4 months

​Fogging oil is for 2 stroke motors, not 4 stroke. Though I could see where it might reduce corrosion in a carburetor.

 

[cwburkeva]

I have fogged and used stabilizer in fuel for 10 years and then didn't have boat out for past 4 1/2. Can't say that it did any harm or provided any longevity (except for maybe the last 4 1/2 - ended up overhauling carb and many other engine parts).

It just became part of the routine and who knows if it helped or not. It only added about 5 minutes to my lay-up and it was the final step.

 

[ondarvr]

​Fogging oil is for 2 stroke motors, not 4 stroke. Though I could see where it might reduce corrosion in a carburetor.

It wouldn't do much for the carb, it would only come in contact with the carb throat, and you dont want it on any of the sensors in an EFI engine.

 

[wrvond]

It wouldn't do much for the carb, it would only come in contact with the carb throat, and you dont want it on any of the sensors in an EFI engine.

Very good point. I was thinking of all those nasty old corroded motorcycle carbs I used to take apart. Completely spaced that it wouldn't make it into the bowl and jets.
Good catch!

 

[oldjeep]

If I happen to be checking my plugs anyways then I'll spray some fogging oil in each cylinder, otherwise I don't do it unless the engine is getting stored for an extended period of time. And in that case never through the intake on an MPI motor, always direct to the cylinder through the plug hole.

 

[thumpar]

When I first got a boat and jetski I went through the whole routine. I haven't done it in years now. Drain it and tuck it away.

 

[Old Ironmaker]

The original owner sold my boat to me and he had it for 12 years from new, 2 stroke Mariners, 115 and a 15 kicker. He gave me a typed winterizing procedure. For the 10 minutes it takes to fog the carbs and the cheap price of fogging oil compared to the cost of running her I do exactly as he suggested. 21 year old motors start first or second turn of the keys, every time. No carb work since I have had her.

No need to fog a 4 stroke especially with fuel injection. It won't hurt anything though. And no more Seafoam to fog right?

 

[thumpar]

The original owner sold my boat to me and he had it for 12 years from new, 2 stroke Mariners, 115 and a 15 kicker. He gave me a typed winterizing procedure. For the 10 minutes it takes to fog the carbs and the cheap price of fogging oil compared to the cost of running her I do exactly as he suggested. 21 year old motors start first or second turn of the keys, every time. No carb work since I have had her.

No need to fog a 4 stroke especially with fuel injection. It won't hurt anything though. And no more Seafoam to fog right?

The fogging oil can be bad with sensors on an EFI/MPI motor. There are instructions on adding oil in the filter or using a separate tank for those motors.

 

[Old Ironmaker]

The fogging oil can be bad with sensors on an EFI/MPI motor. There are instructions on adding oil in the filter or using a separate tank for those motors.

Good to know, I'll pass that on to our group of back yard Marine mechanics. I'm the 62 year old Padawan. When I wrote that it wouldn't "hurt" I was thinking on a 4 stroke with carburation as someone said above.

 

[brian4321]

And no more Seafoam to fog right?

Nope... I'm not sure where I read about that or why I thought it sounded like a good idea but thanks for setting me straight... I did that last November and ended up using the boat in December and again in March so it never sat for very long ... hopefully the first start up after that got the cylinder walls lubed up again before it did too much damage

 

[Chris1956]

Gee, fogging oil is introduced into a motor to keep the rust down. Some folks have cited that 4 cycle motors don't need fogging. I have the opposite opinion, since 4 cycle motors run straight gas. I think they need more fogging than 2 cycle motors. Also, sterndrive motors have a lot more cast iron parts than outboard motors. Since iron rusts, I would think fogging would be mandatory at least for sterndrives.

​Also, when I had my sterndrive boat docked in the salt water, I always ran some 2 cycle oil in the gasoline tank. A very weak mix (~300::1). I wanted to keep the rust down in the intake manifold, as I did not want to replace it. My assumption was that some of the 2 cycle oil would end up on the inside of the intake manifold and keep the cast iron from rusting.

 

[wrvond]

Well, waddayano, Stabil makes fogging oil! Whoda thunk?
Of course they claim you should use it in two- and four- stroke engines. Well, actually they say motor, but we all know that's not correct.
Here's the thing - back in the early 90's, when I lived in Hawaii, I used fogging oil in all my two stroke motorcycle engines whenever they went into storage for six months or more; the cans even specified two-stroke use. The logic at the time was that the combustion chamber got its lubrication from oil that was burned along with the gasoline and parts (such as reed valves) needed to be protected from corrosion. Fogging oil coated everything nicely and kept everything lubricated. When I moved to Texas in 1994, nobody I talked to ever even heard of fogging oil. I went on deployments without fogging my engines. Oddly enough, they all survived just fine. Now, years later, fogging oil is on all the shelves and it is designed to be used in all engines.
The upshot is, if you like it, using it makes you feel better, and you aren't starving your kids to pay for it. I say use it if you want. As for me, I'm filing it under snake-oil.