Fogging MPI engine

[dvan1901]

I have a 2007 Mercruiser 5.0 MPI. The manual calls for making a fogging mixture and disconnecting the fuel line and so forth. My problem/question is, my fuel lines are really difficult to get off due to the triple barb connections and so forth. My fuel rail has a Shrader valve on it; is there a type of fogging spray that connects to this rail to allow for fogging?

 

[Bondo]

Re: Fogging MPI engine

is there a type of fogging spray that connects to this rail to allow for fogging?

Nope....

1 way to do it is to empty the Fuel Filter, then refill it with the mixture, then run the motor....
Or,...
Don't bother at All if the lay-up is only a few months...
Or,...
Pull the sparkplugs,+ squirt the oil in directly to the cylinders...

 

[dvan1901]

Re: Fogging MPI engine

Thanks Bond-O. I asked about the fuel rail as I had read something about it, but it was for a different type of engine. My fuel filter is the canister style so I can pull the top of it, pour some in and run it. I can also spray into the cylinders so that is what I'm going to do. Thank you!

 

[Don S]

Re: Fogging MPI engine

I wouldn't "Empty" any fuel filter on an EFI engine and reuse it. When you dump the fuel out, you could very easily transfer some contaminated fuel to the clean side and let it get to the engine. If you want to use the fogging mixture in the fuel filter method, Great, but put it in a new filter.
Filters are about 6 to 10 bucks. Injecters are $50 each to get cleaned if they get contaminated. That's $400 for 8 injectors.

 

[Jeepster04]

Re: Fogging MPI engine

Taking the spark plugs out is great and all but I like to get some on the valves to keep them from rusting. Putting the fogging oil in a clean fuel filter sounds like a great idea. Just make sure and put some fresh gas in there also. Engine may not run at all if you just put fogging oil in there.

Keep the blower on in the engine bay while working with all that gas.

 

[Don S]

Re: Fogging MPI engine

Putting the fogging oil in a clean fuel filter sounds like a great idea. Just make sure and put some fresh gas in there also. Engine may not run at all if you just put fogging oil in there.

Like I said, put the Fogging MIXTURE in the filter. Not just the fogging oil or stabilizer.

 

[JustJason]

Re: Fogging MPI engine

Dvan, I think you are confused.

Starting with a new spin on fuel filter cannister, fill the canister 3/4 full with gasoline. Then fill the remaining space with 1/2 2 stroke oil, and 1/2 fuel stabilizer. Install the new fuel filter, start the motor and let it run for a minute or 2 then start hosing fogging oil (mercury storage seal) down the throttle boddy untill she conks out or starts smoking a whole bunch, then kill the ignition.

The mixture in the fuel filter is designed to winterize the engines fuel injection system. The fogging oil is designed to coat the engines mechanical internals.
If you get the motor smoking real good then you don't really need to pull the plugs out.

 

[rodbolt]

Re: Fogging MPI engine

DO NOT spray ANY liquid into the throttle body of MPI engines.
its a good way to hydraulic lock a piston and possibly bend a connecting rod.
the intake manifold on most MPI designs are simply not ment to move any liquid and liquids tend to puddle then get sucked in all at once leading to bad things.
thats why the service manual reccomendations changed.
last I read,and it may have changed again, they wanted the engine at a fast idle for 10 minutes running on the solution.
never saw any mention of filling fuel filters with anything but fuel.
yes sometimes accessing things is difficult but must be done to do the job correctly.

 

[dvan1901]

Re: Fogging MPI engine

Just Jason, not confused at all. I do not have a spin on fuel filter; it is a canister filter. It has three bolts on the top, with a handle. You take the bolts off and it pops out (has a rubber o-ring to seal it). Then it has a paper filter and a smaller, flat, wafer looking fuel/water filter. If you look at this diagram, in the larger picture, it is the piece that has the handle towards the back right.
http://www.perfprotech.com/store/assembly/Cool-Fuel-System,12827-50.aspx

actually, this is a better view; it's part number 22, that whole section is the fuel filter:
http://www.perfprotech.com/store/as...s--Bravo(SN-1A343748-and-Below),13884-60.aspx

 

[JustJason]

Re: Fogging MPI engine

Bahhh... you didn't say you had a cool fuel module. Now you really have to grab the rubber fuel line comming of the tank someplace and stick it in a gas can.

Hey Rodbolt. Just curious. I completely believe as to what your saying can happen. But have you ever hydrolocked or seen one because of storage seal? I've done quite a few MPI's by shooting the fogging oil in spurts (as in not dumping a 1/2 a can in a shot) down the throttle plate at fast idle and never had a problem.

 

[rodbolt]

Re: Fogging MPI engine

justjason
yes
an 8.1L
hydrolocked with fogging oil.
when I removed the plugs a few cylinders had the stuff running out. it puddles in the intake manifold of 90% of the MPI desighns on the market due to intake runner tuning.
most tend to run uphill then back down towards the intake port in the head.
thats the entire reason that most marinizers of MPI GM engines came out with this revised procedure.
I aint gotta engineer this crap, I just get to fix it.
follow all pertanint service liturature and it works first time every time with minimal waste of time.
and yes there are a few hulls with a dead headed fuel line so I no longer have to go upside down in the bilge once per year.
quite a few of the hulls I deal with I have dealt with every year for 15 to 20 years.

 

[dvan1901]

Re: Fogging MPI engine

So what is interesting, and lead to my question in the first place, is on the can of SeaFoam spray it talks about connecting the can to the Shrader valve on the fuel rail. I've seen some cans with the valve connector tip so I wondered about it.

 

[Don S]

Re: Fogging MPI engine

You might want to re-read the can. The schrader valves on the fuel rails are all high pressure test connections only, for a fuel pressure gauge. Not a place for fogging, or seafoam or anything else to put IN.

There are cans of fogging oil and possibly seafoam for use on Johnson and Evinrude outboards on the priming solenoid that can be used for fogging and such. But not GM fuel rails.