Fogging a EFI 90 HP Merc 4 stroke?

irv

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Oshawa, Ont. Canada
Just curious who all fogs their EFI 4 stroke engines? Last year, with mine, I only squirted some into the cylinders and rolled the engine over a few times prior to storage but this year I am strongly considering spraying directly into the air filter/plenum area and spraying until the engine stalls or I at least see white smoke coming out of the exhaust. Any concerns with doing this with an EFI engine? I assume not but because I have only fogged out carbed engines before, I thought I had better ask just in case?
(It's a 2007 Merc 90 HP 4 stroke)
 

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Middle of Iowa
I have fogged all my engines I store over winter by spraying until they die - boat engines (FI and carb), mowers, genny's, snowblowers, motorcycles...

The only engine I could not get to die with this method was a Chevy 454 marine engine...even spraying two cans at the same time, it just chugged along.
 
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Upstate NY
I see no issues in fogging your engine. Just keep in mind you want a fog to go in to the engine not a liquid. I have used two cans at once some fall seasons. And not all cans of fogging oil spray out at the same rate.
 
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irv

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Oshawa, Ont. Canada
I see no issues in fogging your engine. Just keep in mind you want a fog to go in to the engine not a liquid. I have used two cans at once some fall seasons. And not all cans of fogging oil spray out at the same rate.
In order to see/get smoke, does the liquid not need to be burned in order to get the fog? I'm confused on your comment but maybe I am doing it right anyway? I usually, with my sleds, spray just outside the carbs and let the air flow suck the product in. Is that what you mean? I usually end up with a bit of product (puddle) left on the bottom of the carbs after the sleds have stalled, which I just wipe up with a clean rag or paper towel.
 
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In order to see/get smoke, does the liquid not need to be burned in order to get the fog? I'm confused on your comment but maybe I am doing it right anyway? I usually, with my sleds, spray just outside the carbs and let the air flow suck the product in. Is that what you mean? I usually end up with a bit of product (puddle) left on the bottom of the carbs after the sleds have stalled, which I just wipe up with a clean rag or paper towel.
Its possible if you sprayed in too much fogging oil at too high a rate it could get into the cylinder as a liquid and hydrolock the engine. That was all I was saying. It may be difficult to impossible to do. As with most things in life - moderation.
 
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irv

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Its possible if you sprayed in too much fogging oil at too high a rate it could get into the cylinder as a liquid and hydrolock the engine. That was all I was saying. It may be difficult to impossible to do. As with most things in life - moderation.
Thanks for the clarification. (y)
 
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NY
I never had a problem. I sprayed the fogging oil into the engine running at a fast idle, when it started to smoke out the place I shut it off. If it stalled it stalled, if it didn't I turned it off when my wife started complaining of the smoke screen in the yard. In all honesty my goal wasn't to stall the engine, just to get it to smoke.
 
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4WD

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Texas
I don’t fog … but if sitting for a while I tilt the motor a day before to let a small bit of oil past the rings …
Figure a couple seconds of smoke is better than a dry cylinder on the low side … (upright I-4)
 

irv

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Oshawa, Ont. Canada
Well, the fogging didn't go so well. I started my engine like normal and began to spray into the opening of the throttle body but because of the butterfly valve, getting the fog spray into the engine was rather difficult. I decided to engage the engine by putting it in gear and that worked better as the butterfly opened slightly but I was unable to stall the engine and it was difficult to see if any smoke/fog exited the exhaust? I got it to stumble so I know it was getting some but it seemed the majority was just running out into my engine bay. Having another person would have helped a lot as I could have instructed them to shut the engine down when it stumbled but by doing it myself, by the time I was able to reach the key the engine was running normal again.
Long story short, I removed the plugs and sprayed directly into each cylinder like I did last year and spun it over a couple times. While removing my plugs I could tell fog had gotten in there as the plugs and the tops of the pistons were wet with the product.
The marina I use to store my boat at had a very expensive product they added to the gas that supposedly lubed/fogged the internal engine parts and treated the gas at the same time, but I have no idea what it is or what it is even called and of course I have no access to it.
 
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