fog a 4 stroke or not?

[Gadgetman]

I am getting different answers to the above question. Several local shops have said that if I fog my four strokes that it will be a real bear getting them started in the spring.The book suggests pouring a teaspoon of oil in each plug hole...am a bit reluctant to that also. What do you guys think?

[Jeremy airjer W]

If its going into storage for more than a couple of months than fog it and stabalize the fuel. All fogging does is give the cylinders a final coat of lubrication to keep everything from corroding. It may take a couple extra cranks, it takes a couple extra to get the lawn mower and snoblower going, to get it started and it will probably smoke like crazy for a couple of minutes. On the other hand I only started doing this maintenance myself about five years ago. I decided my investments were getting more expensive and I wanted to do everything possible to get every pennies worth out of them!

Will it make any difference if you don't? Probably not. Will you notice any difference if you do? Probably not. Is it worth some piece of mind? yes!

[Northlander]

I have also heard mixed opinions on this. I was told by the shop not to fog my 4 stroke but then I have heard that others do it. Anyone who is a certified mechanic that knows the true facts on this?

[ChuckN]

I've heard mixed reports on fogging on outboards too. Personally, I fog all engines (lawnmowers, snowmobile, old cars during winter storage). I've owned small 4 stroke outboards and fogged them all through the carbs and into the cylinders. Never had a starting issue in the spring.

Since a lot of 4 stroke outboards are efi, the only thing you can do is remove the spark plugs and spray oil into the cylinders. It is a good idea to add some sort of oil into the cylinders during storage. Moisture can build anywhere with time.

[Jeremy airjer W]

How about the opinion of an "Auto Technician" with over 10 years of experience?

[Macgyver55]

Again I concur with Airjer. If in doubt, fog it! Sadly I have no personal experience with the new 4 stoke outboards, but see no reason NOT to fog them. I actually think it can sometimes be more advantagous to fog 4 strokes because there are more internal moving parts. A lot does depend on what the weather is like when and where you store it. I had the pleasure of rebuilding my brothers old I/O motor many years ago. In the spring when he went to fire it up it sounded different when cranking and would barely run. We determined that the compression was low on a few cylinders. On teardown I found that some of the valve stems had rusted and seized in place, causing the valves to stick open, and one cylinder had rust marks on the cylinder walls. Needless to say he had to put a lot of money into valve guides and seals etc. and we ended up honing and reringing it as long as it was apart.

I figure a little extra oil never hurt any motor that I know of...but too litle will surely hurt them.

Maybe someone out there has a good reason not to fog. If so speak up, I'm still willing to learn......

[Northlander]

Airjer that would work. Do you know a good one? Thanks for the info.

[mechanictim]

Two cycle fogging oil when sprayed through the carb or throttle body of a running two stroke engine coats not only the combustion area but also the crankshaft bearings, connecting rod bearings, and wrist pins. two cycle fogging oil leaves a heavy almost grease like coating of rust preventive and lubrication. The gasoline and oil mix that normally lubricate these bearings will wash this fogging oil away when starting the engine after storage.

Pouring a little engine oil into the combustion chamber of a four stroke and turning the engine over with the plugs pulled will coat the cylinder walls with enough oil to protect for a few months. The crankshaft bearings etc. will have enough oil on them from normal operation to protect for several months.

Using two stoke fogging oil in a four stroke engine COULD lead to carbon deposits on the valve seats that will effect engine performance. A two stroke engine doesn't have valves in the high compresion area of the combustion chamber like a four stroke and will clean out the heavier fogging oil better than a four stroke. Two strokes are designed to run with oil in the fuel but a four stroke likes its fuel straight up. A lot of people will tell you they fog their lawnmowers etc. with no ill effect, well if you lost 10 to 15 percent of your power in you mower would you notice? lose that from a high performance engine like an out board and you will know right away.

The best advise for your engine will be from the owners manual, these are the people who put their name on the product and provide warrenty coverage.

[Jeremy airjer W]

Good one Northlander!!

Mechanictim, Good Info!

Remeber not all "fogging" oils are created equal. I have been using Deep Creep for many year. For all intents and purposes it is Sea Foam Motor Tune in an aerosal can. It has a lubricant, moisture dispertiant, and a decarbonizer. I will usually run whatever it is out of gas and then run it for a short time by spraying deep creep through the carb. then I blast it with deep creep through the carb until it stalls. the last thing I do is let whatever it is cool down remove the spark plugs and give it a final "fogging" with the Deep Creep. So basically what I have down is a basic upper end decarbonizing followed up with a storage fogging, or killed two birds with one spray can!

[marine_man]

I spoke to the service manager at Crystal Pierz Marine in St. Cloud and he informed me that they fog all 4 strokes that are brought in there for storage (including EFI's). They fog the carburetored engines by spraying the fogging fluid through the carburetor... the EFI is a little more complex... involves removing some bolts in the correct location for access to the intake...

marine_man

[nthomps66]

My Yamaha 4-Stroke Owner's manual says I should fog it before winter storage. So I shall.

[walleyehawk]

My Merc EFI manual says fog it. And every year it starts up on the first turn of the key.

[Mueller]

For what it's worth; several years ago we had a Sears push mower that did a heck of a job cutting the grass at the cabin. For winter we put it in the shed until the next spring when I started it and it smoked like crazy. I brought it to the small engine shop and the piston ring stuck to the cylinder, upon starting, a chunk of the ring gouged the cylinder and the engine was useless. The mechanic suggested fogging the engine on anything that had a motor and was to undergo long term storage. I now fog everything I have and have not had any problems. I feel it's cheap insurance.

Mueller