Winterization question - True or False
 

If you winterize an EFI engine(496 HO, 525, etc) using fogging oil, you run the risk of ruining the airflow sensors. T or F?

If this is true, what is the correct method to winterize these motors?

From what I have read, True. But I have no first hand experience.

The correct method (according to the manual) is to mix in a small plastic fuel tank a 10:1 mix of fuel and 2-cycle TC-W3 outboard oil along with some fuel treatment/stabilizer. They call it a 'fogging mixture'. Connect the fuel tank to the fuel inlet fitting of the engine and run the engine at 1300 rpm for 5 minutes. Done. This is what I do every fall before putting it away for the winter.

It is not recommended to spray fogging oil into ANY engine with a MAF (mass air flow sensor). It can goop on the sensor and skew the readings skewing the computer's self adjustments.

I don't do the mix/fuel can trick.

I run 3 gallons of antifreeze through the engine.
Then I pull the fuel/water separator, dump out 1/2 the gas, and fill it with 2-stroke oil. Re-install and run 3 more gallons through the engine.

I do the same as sydwayz however I use less antifreeze since it is a small block.

Since the MAF sensor is on the intake side, what about blowing the spark plugs out and spraying fogging oil directly into the cylinders?, does this cause any damage?, I have a buddy who bought a boat that has been sitting for 2 summers, he has put fresh gas in it, but, doesn't want to spin the motor over "dry", so, I suggested spraying fogging oil into the cylinders first, any thoughts?

Thanks!
Michael

Perfectly acceptable; yet liable to quickly foul the plugs so be ready for that.

However, the 2-stroke oil in the fuel water separator would be good for him too to lubricate the now VERY dry fuel system (rails, regulators, injectors, etc. assuming it has fuel injection). Carb-motor--fog it a bit and fire it.

It also would not be a bad idea to try and get the lifter valleys moist with oil by pulling off the valve covers. This avoids a dry start cam. If possible, pull the distributor and use a drill to prime the oil system with a drill. There are tools sold to do this.

Actually there is a bit of mis-informormation in this thread..

On the Marine 496's there is NO mass airflow sensor like on a truck. If it did have one you would ruin it or corrupt its readings by spaying oil on it.. What you DO have is a MAP manifold air pressure sensor. It reads the ammount of vaccum or lack of vaccum to help determine proper fuel delivery. If you get oil on this it can corrupt the reading. However it would not be that easy to get oil up & in to it if you were to fog an engine with a mist thru the throttle blade or the pcv type orifice..

On a different note The Parafins in most fogging fluids can cause injectors to stick if you ran it thru the fuel system & it can cause the fog fluid to hang on to some other parts such as sensors so to speak if you were to fog the engine in certain ways. This is why merc, volvo & a few others have now moved to recomending that for extended or off season layups that a mix of fuel stabilizer, 2 stroke oil and gasoline be run thru the fuel system until the engine starts to smoke a bit. This they claim is an acceptable replacement for fogging thru the intake or plug holes..

Hope this helps to clarify things a bit.. :) Jamie

I've always thought the 2-stoke oil in the water separation filter made sense, but now I think I like your idea better. I have my first EFI now, so I have been thinking about this a lot lately.

Thx!

Thanks guys. A buddy who has a 496 non-HO is all worried now because his mechanic used fogging oil. I guess I should ask my guy how he winterized mine!

Great!, thanks for all the help and input, I imagine tearing the distributor out is way more work than he wants to do, so, was curious?, I know in my automotive days several light years ago, you could spin the plugs out and spin the motor over without plugs in it to lube the walls and build a bit of oil pressure, but, was hesitant to suggest this on his motor because of all the EFI/Computer stuff, I didn't know if turning the motor over [either on the starter or with a bump switch] would hurt anything, or fry the computer?, I had planned on pulling the coil wire off first, any thoughts?