make sure the engine is hot enough so the thermostats are open. Otherwise the block will be filled with water and the antifreeze will only be in teh manifolds

some where someone stated you would screw up the air mass meter and that would cause an ecm problem.

This is from Mercury Racing Service Manual Number 6 (GM500EFI engine)


POWER PACKAGE LAYUP

1. Fill fuel tank(s) with fresh (alcohol free) gasoline and sufficient amount of Gasoline Stabilizer and Conditioner to treat the gasoline.

IMPORTANT: If boat is to be placed in storage (with fuel containing alcohol), vapor separator tanks must be run dry at idle rpm. Fuel tanks should be drained completely and Gasoline Stabilizer and Conditioner added to any fuel remaining in the tank. Refer to "Fuel Specifications" for more information.

2. Replace all fuel filters

3. Start engine and check for fuel leaks.

4. Operate engine sufficiently to heat it to normal operating temperature. Shut off engine and change oil and filter.

5. If boat has been operated in salty, polluted or mineral-laden waters, flush cooling system.

6. Prepare fuel system for extended storage as follows:

A. Remove flame arrestor assembly and start engine. While operating engine at fast idle (1000-1500rpm), fog internal surfaces of induction system and combustion chambers by slowly squirting approximately 227g (8 oz.) of Storage Seal or SAE 20W engine oil into engine intake bores. Stall engine by squirting last 57g (2 oz.) of Storage Seal or oil rapidly into engine intake. Turn ignition to OFF.B. Close fuel shutoff valve, if equipped.

C. Remove and discard old water separating fuel filter and sealing ring and install new sealing ring and filter.

D. Clean flame arrestor and crankcase ventilation hoses and re-install.

E. Lubricate all items outlined in "Lubrication".

F. Drain seawater section of cooling system, as outlined in the following section, "Draining Instructions".

G. Service batteries.

H. Clean outside of engine and repaint any areas required with Primer and Spray Paint. After paint has dried, spray Corrosion and Rust Preventive Type II or wipe down with Storage Seal or SAE 20W engine oil.

I. For drive unit, refer to appropriate sterndrive manual.

Seems a little strange to do the foging this way in a EFI engine?

yes it does, so far everything i have seen or heard has said to not spray fogging into the intake...........

Mercury put out a service bulletin a several years ago (2001) that no longer recommends what was printed above. Merc changed from what was in the manual (printed above) and they don't recommend spraying fogging oil in the EFI intake. Here is a link to the service bulletin(you may need to cut and paste the link)http:www.boatfix.com/merc/bullet/01/01_15.pdf Instead of mixing 6 gallons, a small amount can just be mixed in a new water/fuel separator and just run the engine on that.

Yes but that new merc bulletin seems like it will do very little.

Yes, The new bulletins do not reference fogging thru the intake. It also does not specify that you cant fog thru the intake, or plug holes one at a time. (Volvo has a similar bulletin by the way).. The reason for this is Merc & Volvo both feel that the fuel mixed with the 2 stroke blend is adequate protection internally for a single winter layup. Also their main concern is keeping the fuel pumps from from pitting or siezing as well as the injectors..

I would not be overly concerned with just following the factorys guidelines for a single season lay up, but if you needed to pickle the boat for it to sit for seasons (plural) fogging in addition to the fuel mix bulletin shouldnt hurt..

If you choose to fog in addition to the fuel mix it must be done thru the intake, or thru the plug holes one at a time.. Also you would still need to run the recomended fuel mix thru it..

DO NOT put fogging fluid in the fuel mix as some of the chemicals in the fogging fluid can make or cause the injectors to stick or become sticky.

BTW... There is not a mass air flow sensor, or mass air flow meter on these engines like there are on a car or suv.. You are thinking of the Map sensor (manifold air pressure sensor) which monitors vaccum and barometeric pressure.. They are not the same as a Mass airflow sensor or mass air flow meter..

Lastly this bulletin would not apply for carbbed applications.. THey should still be fogged & the fuel systems treated traditionally..

Hope my 2 cents was usefull to some of you..
Jamie / Lakeside

Do you leave your fuel tanks full or empty? Regular gas (prem 95)

My preference is to treat the fuel system with stabilizer & leave the fuel level low..
With this new ethanol blend junk, why would you want to buy a full tank of fuel only to let it spoil over the winter.. If you stabilize the little ammount thats there and then fill up with fresh fuel in the spring it will burn easier and be less less likley to cause any possible dammage.. Jamie / Lakeside

Seems to me it might still be best to remove the thermostat for this operation. Also if you are running the exhaust thru the prop does all the exhaust go out there or are the any other exits? I know a small amount may go by the silent choice valves but it looks to me like there might be a couple of small ports on each side of transom assembly area next to the gimble ring.