A question for Mercury outboard techs

[muc]

Fogging a newer 4 stroke EFI engine

I've been retired from the boat business for awhile and never did a lot of outboards, but we always ran them on a storage mixture for layup.
I was looking at a owners manual for a newer outboard and see Mercury doesn't recommend this on outboards.

Here is what's in a new outboard owners manual-
IMPORTANT: This outboard is equipped with a closed fuel system. Fuel within the engine's fuel system, other than the fuel tank, will remain stable during normal storage periods without the addition of fuel treatment stabilizers.

But this is what's in the owners manual for a MerCruiser-
Preparing Power Package for Storage—MPI Models Multipoint fuel injection (MPI) systems must have a special mix of fuel, stabilizer, and lubricant, completely fill the fuel delivery system. This fuel mix stabilizes the fuel and lubricates the fuel pumps, fuel pressure regulator, fuel injectors and, reduces internal oxidation of the fuel system metal components.

At MerCruiser school they told us the storage mix is more to protect the fuel system (pumps, injectors and etc.) then it is to protect the cylinder walls and rings. The outboard manuals still recommend squirting storage seal through the spark plug holes.

My question is why the difference between these products? They are both basically using pretty much the same components. Only thing I see is the I/O has steel fuel rails and the O/B has plastic.

Do shops that winterize these 600 HP motors really pull 24 spark plugs to squirt an oz. of oil in each hole instead of hooking up a storage mix tank? These motors are like $85,000 a piece.

 

[Scott Danforth]

I can reach out to a few engineers I still know at Merc this coming week. However the 600hp motor is a variant of the LS motor and the I/Os of Mercruiser are a variant of the SBC, but the fuel system and storage requirements would be the same

They do have different engineering teams, and they do not communicate with each other.

 

[muc]

I can reach out to a few engineers I still know at Merc this coming week. However the 600hp motor is a variant of the LS motor and the I/Os of Mercruiser are a variant of the SBC, but the fuel system and storage requirements would be the same

They do have different engineering teams, and they do not communicate with each other.

Hey Scott, That would be great. I would be very interested in what your contacts have to say,
I called Mercury consumer tech support today. Was told that the "manual is the manual". But that running a storage mix thru an outboard wouldn't hurt and would be better for the engine. "just don't skip pulling the plugs an squirting some oil in there"

I guess if I owned a pair of 2022 250HP Mercs , I would run them on storage mix as part of winterization.

 

[Scott Danforth]

Muc, see your PM's...... going with Right Hand not communicating with left hand