Fogging MPI vs EFI

[SeaRay]

I have read on here that if you have a MPI engine you should fog it by adding 2-stroke oil to the fuel / water separator filter.

Is that still true with a EFI engine?

I believe my 1999 5.0 Liter engine is a "throttle body" EFI engine?? I was told I could squirt the fogging spray in the throttle body???

But I also have the filter (and replace it every fall anyway) so how should I fog the engine??

Thanks

 

[Go Aweigh2452]

I have a 6.2 Horizon engine...
My engine extended storage directions say to mix 5 gallons of unleaded 87 octane with 2 qts 2 cycle TC-W3 outboard oil and 5 ozs fuel treatment/stabilizer in a 6 gallon can.
Run the engine for 5 mins at 1300 rpm from the 6 gallon can ensuring you have cooling water. Slowly return throttle to idle and shut down and drain engine of raw water.

 

[Lazy Daze]

SeaRay,

Since yours is an EFI, yes, you could spray into the TB. Or, you could pour out about half the gas that's in the separator and fill it back up with a few ounces of 2-cycle and some ethanol-fighting stabilizer (Startron, Marine Stabil, etc) and then run that for about 5-7 minutes. Either way would be fine. Note: You won't see nearly as much (almost none) smoke using the filter method as you would through the TB.

I use the separator method on my own boat (using the old filter), then change the filter in the Spring. It's really not that big of a deal if you put the mixture in a new filter - it's just the way I prefer doing it for own boat, since I have the time to do it.

 

[sbw1]

If you store inside a heated building you don't need to fog, just stabilize your fuel.

 

[srdancer90]

My marina is no longer using the Merc two cycle oil as a fogging mixture,instead they are using CRC fogging storage mixture in the gas. However they are not releasing the mix quantity. Has anyone used CRC,s liquid mix in their gas? Why cant you fog an MPI through the plenum?
2004 320 DA t/5.7 MPI

 

[SeaRay]

Thanks for the clarification.

Not sure which way I'll do it, but It is nice to know that I have an option.

 

[Last Dollar]

I'm considering adding a shutoff valve from the tank and a T connector between the tank and engine. This would enable me to shut off the gas, hook in a small tank with the winterizing mixture and run the engine. After fogging is finished I just close a valve, unhook the fogging mixture tank, and open the valve at the permanent tank. Has anyone done this????

 

[TheLucille]

I have read on here that if you have a MPI engine you should fog it by adding 2-stroke oil to the fuel / water separator filter.

Is that still true with a EFI engine?

I believe my 1999 5.0 Liter engine is a "throttle body" EFI engine?? I was told I could squirt the fogging spray in the throttle body???

But I also have the filter (and replace it every fall anyway) so how should I fog the engine??

Thanks

MPI and throttle body injection (TBI) are both EFI. Yes, with TBI you can fog into the engine, you still need to shut down the engine while spraying.

I'm considering adding a shutoff valve from the tank and a T connector between the tank and engine. This would enable me to shut off the gas, hook in a small tank with the winterizing mixture and run the engine. After fogging is finished I just close a valve, unhook the fogging mixture tank, and open the valve at the permanent tank. Has anyone done this????

Fogging oil needs to get inside the cylinder walls/heads and stay there, by running it through the gas you're not really accomplishing anything that the fogging oil is there for. You need to shut the engine down while fogging so that the fogging oil sits in the cylinders, when the engine is running as a mixture it is burning what's injected into it.

 

[Last Dollar]

The owners manual says to run the engine with fogging mixture in a seperate tank for 5 minutes at 1300 RPM. Bring back to idle very slowly and shut engine down, reconnect original onboard tank.

Who's right??

 

[951tom]

I'm considering adding a shutoff valve from the tank and a T connector between the tank and engine. This would enable me to shut off the gas, hook in a small tank with the winterizing mixture and run the engine. After fogging is finished I just close a valve, unhook the fogging mixture tank, and open the valve at the permanent tank. Has anyone done this????

I was thinking about doing the same but using a Moeller 3-way tank valve. I'd want some way to close off the 2nd fitting in case the valve got turned.

 

[phughes200]

I had the same question. I have a 2000 210BR with the 5.0 EFI engine that I want to fog.

If I put the two oil in the fuel filter, how long and at what rpm should I run the engine?

I am also confused if it is safe to use the fogging spray in the throttle body instead.

The manual says to shut off the fuel supply and run the engine until the fuel/oil mixture is exhausted. At this time, I don't have a fuel cutoff.

 

[Lazy Daze]

I, personally, haven't come across any issues with the limited number of sensors that an EFI has, compared to an MPI and spraying fogging oil into the throttle body. It could be that the MPI sensors are more finicky than the EFI, I don't know. But, the way we normally do it at the shop (and how I do it with my boat) is to do the "cocktail" method.

If your fuel is treated (a little stabilizer is part of the cocktail recipe) you're fine with not running it dry. If you did want to run it dry, just pinch the fuel line closed.

 

[SeaRide]

The Merc. maintenance/procedures manual for EFI engines does not mention fogging spray as an acceptable method. I usually put fuel stablizer in the tank prior to my last run to ensure that the fuel system prepared for storage. Then use the mixture method as stated in the manual. The manual states to run the engine at idle speed. Once you see blue smoke exting the exhaust, turn of the engine.

 

[Lazy Daze]

What I forgot to mention about spraying into the throttle body on an EFI... You're not doing anything for the injectors, and that is one of the main things you want to do. There's this tiny drop of fuel that stays on the tip of the injectors and you want that fuel to be cocktailized. There 'ya go - brand new word!

 

[PIBYC]

I have owned various boats over the last 25 years and have NEVER fogged an engine. The marina I currently dock at also does not fogg any of the 400+\- boats they haul each season. With over 400 hrs on my last boat we have had no adverse consequences.