fogging

have1998mercury 50hp 4 stroke bigfoot ,what is the correct way to fog engine for winter storage,thanks in advance

Re: fogging

Remove carb air box, start up motor on muffs and spray fogging oil alternately into each carb intake until motor smokes a lot, then turn off motor, all shiny internal parts like bearings, journals, pistons,wrist pins, etc. are now coated with a protective lubricant to prevent corrosion while motor is laid up for winter. Good Luck!

Re: fogging

robert's post is specific to 2 stroke engines. IMO, the correct way to fog a 4-stroke engine is to not fog it . Add oil to your cylinders through the spark plug holes and turn the crank manually or with the starter if you want added protection for the cylinders. Spraying oil in through the intake and burning it doesn't offer the same quality coating. The only additional components you're lubricating with fogging oil if you spray into the carb is your carb throat, intake manifold and intake valves. And even those you can fog without running the engine by cranking the starter with the leads off the plugs to draw some air through while spraying. Everything else is below the piston rings and is lubricated by normal (pressurized) motor oil.

Re: fogging

Fogging is usually more associated with 2 stroke motors since no oil/protection in the crank area, but it may be important for a 4 stroke since no oil/protection in the cylinder/combustion chamber/valve area...and what's it gonna hurt?, especially if your boat/motor is stored in a high-humidity area near a river/lake/ocean. Piston rings and cylinder liners are cast iron/steel and prone to corrosion. Whatever works!

Re: fogging

robert graham said:

Remove carb air box, start up motor on muffs and spray fogging oil alternately into each carb intake until motor smokes a lot, then turn off motor, all shiny internal parts like bearings, journals, pistons,wrist pins, etc. are now coated with a protective lubricant to prevent corrosion while motor is laid up for winter. Good Luck!

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Perhaps you missed the point about this being a 4-stroke. Spraying anything into the intake will not get anywhere near rod or main bearing journals, or the crankshaft. It will coat the cylinder walls and valve stems however. The oil pump in the engine will protect the other internal parts with sufficient oil to last for a couple of years. And if this engine happens to have a bunch of sensors, spraying stuff into the intake can damage those sensors -- especially air mass sensors. and oxygen sensors,

Re: fogging

So you all are saying forget the fogging oil and just dump some 4sroke oil in each spark plug hole and turn the flywheel a few times and thats it?

Re: fogging

most I have done is spray a bit of WD-40 in the cylinders on a long term storage (over 6 months).

I personally do not fog anymore.

Re: fogging

Silvertip said:

Perhaps you missed the point about this being a 4-stroke. Spraying anything into the intake will not get anywhere near rod or main bearing journals, or the crankshaft. It will coat the cylinder walls and valve stems however. The oil pump in the engine will protect the other internal parts with sufficient oil to last for a couple of years. And if this engine happens to have a bunch of sensors, spraying stuff into the intake can damage those sensors -- especially air mass sensors. and oxygen sensors,

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Yep, I missed the 4 stroke part...

Re: fogging

Scott Danforth said:

most I have done is spray a bit of WD-40 in the cylinders on a long term storage (over 6 months).

I personally do not fog anymore.

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WD40 would be of little value in this application.