Winterizing a MPI Engine
 

I come from the world of carborated engines. Now I find myself in the midst of technology, but no carborator. Here is my question, when winterizing, I am used to fouling the engine through the carb. How is the best (yet easiest) way to foul the engine on a MPI engine (377 scorpion mercruiser). Any suggestions greatly appreciated.

My Merc Service manual says take off your water separating fuel filter, pour the gas out into a container, add 2 ounces of 2-stroke oil into the container and mix it up. Pour the mixture back into the filter and screw the filter back on. Disconnect the line from the gas tank to the fuel filter housing inlet. Start the engine and run it until the motor stops running. Take off the old filter, put a new one on (oil on the rubber ring like oil filter changes), reconnect the line to your tank and your done.

I did mine this way but I also added a little fuel stablizer with the mixture. It worked great.

Merc has a new procedure for this that supercedes the owners manual method of filling the Fuel filter:

Fogging Mixture :

In a 6 US gal (23 L) remote outboard fuel tank, mix:

5 US gal (19 L) regular unleaded 87 octane (90 RON) gasoline.

64 fl oz. (1.89 L) Mercury or Quicksilver Premium Plus 2-Cycle TC-W3 Outboard oil.

5 fl oz. (150 mL) Mercury or Quicksilver Fuel System Treatment and Stabilizer, OR 1 fl oz. (30 mL) Mercury or Quicksilver Fuel System Treatment and Stabilizer Concentrate.

1. Disconnect and plug boat’s fuel line from Water Separating Fuel Filter inlet.

2. Connect remote outboard fuel tank (with the fogging mixture) to the inlet of the Water Separating Fuel Filter.

3. a. Cool Fuel models: Start and run engine at 1300 rpm for 5 minutes.
b. VST models: Start and run engine at 1300 rpm for 10 minutes.

4. After specified running time is complete, slowly return throttle to idle rpm and shut engine
off.

That's the way my 496 HO manual reads too.

Wow, 5 gallons of fuel in a bucket...Sounds dangerous.

My winter "downtime" is only about 4 months. Do you guys think I need to fog my MPI engine? I do perform all the other recommended winterizing things.

Thank you for all the input. I will let you know how it works.

Quote:

---

Wow, 5 gallons of fuel in a bucket...Sounds dangerous.

---

NO !!!!!!!!!!!!!!!!!!!

In a 6 US gal (23 L) remote outboard fuel tank , mix: ......

damnit read :mad:

Anybody know why Merc changed to this new method? I was wondering if the old way caused some problems that I may not have heard about.