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'95 Mercruiser 350 Mag TBI Fogging

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pwskicat

Regular Contributor
The service manual prescribes adding 2 oz. Quicksilver Two-Stroke oil to the fuel filter/separator, running the engine at idle for two minutes and replacing the fuel filter/separator. Can't I just spray fogging oil in the throttle body? Note: This is a throttle-body system with two injectors under the flame arrestor, not multi-point injection. Thanks for yr help.
 
Add Sta-Bil 360 Marine fuel stabilizer to your fuel tank at the correct ratio. Run the engine until it's warm and the stabilized fuel has run through the whole system. If you like, you can spray fogging oil into the throttle body to coat the intake, valves and pistons. It probably isn't necessary, but doesn't hurt either.

KJ
 
Thanks, KJ. This will save me from having to install new fuel filters every year on a boat that runs about 10 hours a season. Almost have the top speed issue from my other post worked out on this engine as well. Will be (I hope) posting a closing post on that next week.
 
The Stabil takes care of the fuel and the fuel system.....and I'd suggest fogging the cylinders.....thru the TBI unit is fine....
 
I put Stabil in every gallon of gas that goes in the boat. I also dose the tank at the end of the season. Thanks for the tip!
 
For over-winter storage you do not need to "fog" the engine or add fuel stabilizer. If laying up for say 5 or 10 years, then yes. However for such long term storage, it's best to drain the tanks. There will always be a couple of microns worth of oil coating everything inside the engine. When the engine is running, none of the parts in motion actually come into contact with each other. This coating stays put until the next time you start it. Within half a revolution, the hydrodynamic buffer is fully built up again.
As for the fuel, gasoline will last indefinitely if stored away from light and oxygen (you see those tank farms around distilleries? Yeh the gas sit in those for a loonnnggg time and they don't put stabilizer in it) So, sitting in the tank is a great place for it to live unless some other factor like thermal cycling has any effect. You want to either run the tank down to a small amount so you will add new when you recommission, or fill it to the top so that there is no room for air. Leaving space for air is not particularly bad, but shouldn't be left long term.
 
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..."For over-winter storage you do not need to "fog" the engine or add fuel stabilizer"

I strongly disagree with the idea of not adding fuel stabilizer over the winter. That's begging for trouble. Agreed on the fogging, however.

Jeff
 
If you understand the chemistry of gasoline, you'll know why stabilizer is not needed. If it's just something you believe in on faith, well, ok then.
 
Virtually all gasoline sold nowadays has ethanol in it, up to 10 %. The stabilizer helps prevent to creation of the dreaded "white gook", a liquid that goes right through filters and separators and can not be made to burn (so far).

I'm surprised you haven't heard of what damage ethanol can do by now.

Jeff
 
pwskicat said:
The service manual prescribes adding 2 oz. Quicksilver Two-Stroke oil to the fuel filter/separator, running the engine at idle for two minutes and replacing the fuel filter/separator. Can't I just spray fogging oil in the throttle body? Note: This is a throttle-body system with two injectors under the flame arrestor, not multi-point injection. Thanks for yr help.
Click to expand...

In answer to your question re; TBI:

Yes..... if you were to spray the fogging solution simultaneously and directly into each throttle bore WITHOUT hitting an air sensor...... it could be done.

Keep in mind that;
...... you will want to spray an equal amount of fogging oil into each plane of the intake manifold. (if you miss one plane, you will have missed 4 cylinders)
...... you will want to have a helper with you as to hold the 1,200 RPM while you introduce the fogging oil. The helper will hold the throttle position while you continue fogging until all comes to rest after the ignition has been cut!


As for the oil-enriched gasoline in the fuel filter...... I would mix the oil/gas in a separate container and would then add it to a new and empty fuel filter cartridge.
I see no reason for replacing the filter afterwards (as per the service manual).


***********************************************

This is my take on laying up a gasoline Marine Engine for the winter:


Understand that the intent is to operate the boat again next coming Spring time. However, in the event that something prevents next season's operation, if winterized correctly your engine, etc are ready for an extended lay up.

..... Stabilize the fuel in the fuel tank, and do so upon coming in from your last outing. This ensures a good mixing.

..... Many owners will change engine oil (and oil filter) at this time to eliminate any acidity from within the existing engine oil. I would suggest operating the engine upon oil change completion.

..... As for gasoline being stored ...... understand that the lighter molecules tend to evaporate during storage. Most good fuel stabilizers help to ensure that these lighter molecules do not undergo evaporation, and that the fuel remains in good usable condition.

..... Pull the seawater pump impeller and do a 8 to 10 second "dry start"! This will allow you to blow the exhaust system dry. You will not harm anything by doing so!



True cylinder "fogging" is to occur dynamically and is used for carbureted engines ONLY.
The fogging solution is introduced into the intake air system of an operating engine.
In order to NOT allow combustion to degrade the fogging solution, the Ignition Source should be "cut" while the dynamic process is continued.
An approximate 1,200 RPM (at time of ignition cut) ensures that the rotating assembly will continue during the continued fogging process!
As the rotating assembly comes to rest, the un-burned fogging solution is given it's best opportunity to coat and protect the intended surfaces.


We should NOT attempt to fog TBI, EFI, MPI systems using the conventional "fogging" method!
These systems incorporate air sensors that could become damaged if an oily fogging solution was to accidentally enter.
Instead of using the conventional "Fogging" method, these systems call for introducing an oil-enriched fuel mixture via the normal fuel delivery system.
Although easy and simple to do, the oil-enriched fuel mixture is cut the moment that the ignition system is cut.


If the TBI, EFI, MPI air intake system was to offer a port for introducing the Fogging solution (one that would by-pass the air sensor and reach both planes), then it would become possible to "Fog" a TBI, EFI, MPI system.

And..... DO NOT be tempted to use this or like winterizing systems:
https://www.amazon.com/review/R3BD7X6QC3KCFR/ref=cm_cr_pr_viewpnt




.


 
Ricardo, many thanks for your informative and helpful info. I'm curious; what air sensors are in the TBI system of my 1995 Mercruiser 350 Magnum Tournament Ski, Ser. #OF562552?
 
pwskicat said:
Ricardo, many thanks for your informative and helpful info. I'm curious; what air sensors are in the TBI system of my 1995 Mercruiser 350 Magnum Tournament Ski, Ser. #OF562552?
Click to expand...

I think that with TBI you are OK. My comment was more for those with MPI etc.

Just make sure to get both planes, and to keep engine RPM up enough to allow continued rotation after cutting ignition.


.
 
fastjeff said:
Virtually all gasoline sold nowadays has ethanol in it, up to 10 %. The stabilizer helps prevent to creation of the dreaded "white gook", a liquid that goes right through filters and separators and can not be made to burn (so far).

I'm surprised you haven't heard of what damage ethanol can do by now.

Jeff
Click to expand...
I agree that ethanol-mix fuels can do damage to some components, but the separation thing is not an issue over the course of one winter season of 3-5 months. Ethanol has nothing to do with a gasoline's "stability". A stabilizer is not necessary. This isn't the thread to hash this out.
 
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Ethanol plus water plus time equals the White Gook.

Here's what it looks like. Not sure how long it takes this crap to form, but why take a chance?

Jeff
 
If you read any of the OEMs' warnings about "modern" gasolines, 30 days is the 'shelf life' before degradation is likely to occur.....stabilizer extends the shelf life ..... just chemistry.....

And sepration will happen overnight if the conditions are correct....
 
All good points about the sensors and avoiding exposure to fogging oil.

What if you were to inject fogging oil through the schrader valve on the fuel rail? I'm not saying TO do it, I'm just wondering if that would work? Are the injectors okay with setting for months in the presence of that oil?

What I'm thinking is the pressurized cans of Evinrude fogging oil that you can use with an 'injector' attachment for a schrader valve.
http://www.marineengine.com/newparts/part_details.php?pnum=OMC0777186&pass_title=0777186+%3A++Fogging+oil+can+with+regular+cap.+If+you+need+the+injection+hose+for+the+service+valve+add+part+%3Ca+href%3D%22http%3A%2F%2Fwww.marineengine.com%2Fnewparts%2Fpart_details.php%3Fpnum%3DOMC0763644%22%3E0763644%3C%2Fa%3E.

[url]http://www.marineengine.com/newparts/part_details.php?pnum=OMC0763644

[/URL]Or maybe just CR Engine Storage Oil? https://www.amazon.com/CRC-Marine-Engine-Fogging-Engines/dp/B003OUG0OI

Many of the late model Evinrude and Johnson carb'd outboards came with a schrader valve on the fuel rail that was used to inject fogging oil for long term storage. This fuel line only saw about 6PSI so it is definitely different than the fuel rail on the TBI. But, if this could work it might be an option.
 
Hi guys. Thanks for all the tips.

I'll be adding Stabil to my fuel tank because I've fallen under the sway of the global gasoline stabilization cartel and out of habit.

Can't inject anything into the fuel rails via schrader valves, as there aren't any. This engine is TBI, not MPI.
 
@Ricardo: The first guy who sold me an inboard (1983 Ski Supreme, Pleasurecraft Marine/Ford 351 Windsor, carbureted), showed me how to change the oil, run Stabil through the fuel system, drain the block, tranny cooler and exhaust manifolds; then fog the engine. Twenty years later, the guys I was paying to winterize my inboard (1992 Mastercraft Prostar 190, Mastercraft Ford 351 Windsor, carbureted) put Stabil in the gas, changed the oil and filled the raw water cooling system with pink antifreeze, but never fogged the engine. Now I'm back on my own. Now I'm back to doing it myself for the first time in many moons with this Mercruiser. I know Stabil, draining the cooling system and oil change are mandatory. What about the rest? Fog or not? Antifreeze or not? Thanks for yr help.
 
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pwskicat said:
@Ricardo: The first guy who sold me an inboard (1983 Ski Supreme, Pleasurecraft Marine/Ford 351 Windsor, carbureted), showed me how to change the oil, run Stabil through the fuel system, drain the block, tranny cooler and exhaust manifolds; then fog the engine. Twenty years later, the guys I was paying to winterize my inboard (1992 Mastercraft Prostar 190, Mastercraft Ford 351 Windsor, carbureted) put Stabil in the gas, changed the oil and filled the raw water cooling system with pink antifreeze, but never fogged the engine. Now I'm back on my own. Now I'm back to doing it myself for the first time in many moons with this Mercruiser. I know Stabil, draining the cooling system and oil change are mandatory. What about the rest? Fog or not? Antifreeze or not? Thanks for yr help.
Click to expand...

OK.....

...... stabilizing the gasoline is up to you. I believe that it does prevent the degradation of the fuel, and it is certainly an advantage for the fuel that is left in the carburetor.

..... draining the raw water from cylinder block/heads is mandatory. Freeze damage is very un-forgiving, and is costly to repair!

..... the oil/filter change is NOT mandatory if the oil does not have many hours on it.

..... fogging.... again, this is up to you. I believe that proper fogging offers an extra measure of protection. You can adequately fog a carbureted engine in 8 to 10 seconds. For a V engine with a dual plane intake manifold..... be sure to spray equally into each plane!
See my suggestions re; cutting the ignition as you continue fogging, as to not combust the fogging oil.

..... adding antifreeze???? There is little to no advantage regarding preventing rust scale within the cooling jackets. In fact, the rust scale that may occur during the Lay-Up is paled by comparison to that which occurs during the normal operating season.
Be careful if you do this! Many owners who do, end up finding a cracked cylinder block or cracked cylinder heads come Spring time due to "dilution" that was not counted on.



 
2004 350 Mag MPI (carburetor)
My question is not fuel stabilization (I believe in it). My question is my weatherization process (year 2). I don't believe my 3-point drain system + vent gets all the water out of the water jackets (is a trailer boat level?) so I winterized with a external Camco tank with -50 fluid (no dilution, done twice - 10 gallons). However, now with the engine filled my only choice for fogging is through the cylinders and bumping the engine which a real pain in the butt because finding the plug holes with my modified socket is a finger tip exercise. I've reviewed Service Manual 32.
 
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