Mercruiser MPI new fogging lay up procedure

QBhoy

Fleet Admiral
Joined
Mar 10, 2016
Messages
8,348
Jeez...after reading the updated bulletin from Merc about laying up an MPI.....really ? That much 2 stroke oil ? Not sure I'll bother with this one !
Surely I'd be better just sticking a small amount down the plug holes and turning it over (without start) a few times ? Not sure I fancy that amount of 2Stke through the injectors. Last time I did it, I ran it for the last 10 mins of the year with a tiny amount of 2 stroke in the tank...would have been less than 100/1...at best. What they are suggesting, running off a remote tank and a mental ratio ! Not sure about that one at all.
Thoughts ?
 

tpenfield

Moderator
Staff member
Joined
Jul 18, 2011
Messages
18,137
I did the prescribed Mercruiser procedure once . . . and found it to be a bit labor intensive with using a remote tank, etc. So, I have made some adjustments that fit into the rest of my winterization procedures.

1) First, I drain the fuel tank (pump the fuel out until I get air) and put most of the fuel in the cars.

2) I save about 9 gallons of the fuel and add 1 gallon of 2-cycle oil, plus stabilizer, to get the 10:1 fogging mix . . . really more like 9:1 at that point.

3) I pour the 10 gallon mix back into the fuel tank . . . there are probably a few gallons of fuel that won't pump out . . . so in total there may be about 12-13 gallons of fuel and the mix becomes slightly less than 10:1 (who cares :rolleyes: ) So that is now my 'fogging fuel'.

4) I then use the 'fogging fuel' to run the engines for the winterization - warm-up, antifreeze, draining, etc.

5) The remaining fuel stays the winter in the tank and is used for the Spring initial start-up to provide some extra lubrication. I usually run a high concentration of fuel injection cleaner at that point by mixing about 4 bottles of the stuff with a gallon of fuel and add that to the tank.

6) Once everything is good-to-go for the next season, I put 100 gallons or so in the tank, diluting the remaining 2-cycle fogging mix down significantly. Then run regular fuel for the season.
 

QBhoy

Fleet Admiral
Joined
Mar 10, 2016
Messages
8,348
Thanks TP....has it had no ill effect on the injectors at all ? Just seems really rich to me.
 

tpenfield

Moderator
Staff member
Joined
Jul 18, 2011
Messages
18,137
Thanks TP....has it had no ill effect on the injectors at all ? Just seems really rich to me.

No ill effects . . . even at 10:1 fuel/oil it is pretty diluted from a viscosity standpoint.
 

pwrplay

Seaman Apprentice
Joined
May 20, 2008
Messages
39
I have a 2015 5.0L MPI EC. Does this procedure apply to all years and models of MPI's?
 

theBrownskull

Chief Petty Officer
Joined
Jun 23, 2012
Messages
625
I have a 2011 5.0 MPI (ECT) and with help from Don S, who is no longer with us, was given a procedure. I included the post. The thing is that the Merc Dealers have been told not to do this due to possible fouling of the catalytic converters.

I know several people who do it and several who don't with the same results. Your guess is a good as mine. Hopefully someone with far more knowledge than me will chime in.
 

pwrplay

Seaman Apprentice
Joined
May 20, 2008
Messages
39
Great , thanks for the info BrownSkull. I am going go ahead to lay the engine up as per the manual.
 
Top