Fogging question...
 

1995 502 MAG EFI

After running antifreeze thru the cooling system, I pull the coil wire off and spray fogging fluid into the throttle body.
When I do that, I slide the throttle lever forward to open the blades and then spray fluid into the housing as I crank the starter to turn the engine over.

Question is , is the engine adding fuel to the fixture when of I do this

Just as it would under normal start conditions yes

well that sucks, the fuel is washing out the fluid.

So how do I fog and efi, pull the plugs??

With throttle in WOT position the ECM is placed in flood mode, which keeps the injectors from firing. Even if they were firing it would not be that much fuel

Another issue I would be more concerned with is fogging oil in the intake plenum. MPI motors should not be fogged because it coats the sensors. There is a tech bulletin out saying to mix up a gas and 2 cycle oil mix and run the motor on remote tank, which moves this stuff thru the fuel system

Thanx for the replies.
In previous years I would drain the metal spin on fuel filter and spray a few ounces of fogging fluid in it and crank the engine on that.
Each spring on the first day of boating the engine would stall after a short bit off running and take a very long time to restart.
I assumed that was due to my fogging method, so I decided to change that.
Sounds like I may just not fog it.

Might not be the best way, but I don't fog mine

not one marine OEM engine manu has ever recommended fogging a EFI / MPI thru the intake. One is all your doing is coating the intake track and the runners alot with fogging oil and 2 is it messes up the map sensor and in apps that have a TMAP it really messes up those. And also depending on if applicable and location the fogging oil is messing up the IAT sensor. Also not good for the IAC to be coating them with fogging oil. Next is if your app has a IAC muffler you are really hurting the IAC causing a restriction.


Volvo penta come out with the best way to lay up marine engines in 1996. Merc followed that same procedures in 2001. But with way too much 2 stroke oil in the mix for a jist.

If you are going fog an efi engine, mix some 2 cycle oil or Marvels' Mystery oil into the fuel inside the water sep fuel filter.
Then after fogging, replace the fuel filter with e new one filled with fuel and a little Stabil.

My only concern would be the oil plugging the filter. I would imagine the straight fuel in the Spring would pretty much clean it out though.

have to warm up the engine to its opt temp as well. So do that first if one is going to add oil to the fuel water sep filter. IMO depending on size of filter one is going to run out out the mix first - its best to use what the all the OEM s recommend a remote fuel supply / tank with the mix.

Some of the fuel filers hold LESS than 16 oz of fuel but of course the bigger the filter the more capacity, 2 stroke oil is not going to hurt the filters as many 2 stroke outboards run the same filters and some even use a smaller fuel water sep filters, for an example the Merc optimax outboards. The optimax has a water detecting sensor screwed into the bottom of that spin water fuel sep filters -- it is half the size of the filters we commonly use., They are the same micron ratings as the common spin on filters that is used for sterndrives ---- my point is that 2 stroke motor oil for outboards is ran thru the fuel filters all the time without any issues.

Also like I said many 2 stroke outboards use the exact same spin on filters as I/O -- inboard apps. 2 stroke outboard motor OIL is the best solution to use for lay up at the CORRECT MIX RATIOs so again IMO it is best to premix a correct ratio in a 3 or 6 gallon remote tank and run it thru for 10 to 20 mins --- engine fully warmed up.

EVEN for CARB engine s the same procedure to follow this practice. The least amount of issues take place with these procedures. Water and or condensation is the worst thing for the internals of the filters and fuel along with all fuel related parts. Water is a killer.

Fuel samples is the another most important testing procedure in the mix for winterizations and thru out the year. Quality fuel stabilizer for the mix as well. Some do not last that long and keep in mind - they ( fuel stabilizers ) only LAST UP TO A YEAR as most even state that on the label.

keep in mind as you are starting the engine - with that said --- the poured oil and stabil mix in your fuel filter is instantly changing the ratio of your mix because NEW gas is entering the fuel filter from the gas tank. You have deluted the effective mix especially as soon as the engine starts - fresh gas entering the fuel filter. So think about how you want to do the mix and the procedure thats best for you and your app. If you are in humid climates I would want the best corrosion protection..

The ratio mix is important for lay up especially long timeframe lay ups.... Hope that make sense . For me, I hold the liability when I winterize so I try to do IMO what is best to have the least amount issues during spring commission with marine apps.

What about just pulling the spark plugs, pulling the coil wire and cranking the engine while spraying fluid in one cylinder at a time.
It is a bit of work but my Formula is a single engine so lots of room.
That would bypass any intake sensor issues.
Only downside side I see is blowing the fluid out the exhaust and spark plug port while moving around the cylinders.

I guess you would still need to disconnect the fuel supply at some place though.

I realize that, but mine is a single 502 and there is lots of room to work in the engine bay.

Just did mine a few weeks ago. Did the soup mix in a 3 gallon container. Remove filter and drain. Primed new filter and started up. It ran for a few minutes before you could hear the difference in sound of the engine, ran a little rougher. You can also smell the oil in the exhaust. This was on a 496.