Carb Icing & Silkolene Pro FST.

[Steve]

The humidity and dew point in my locality for tomorrow looks like a healthy contender for high risk carb icing and I wondered whether anyone had experience with using a fuel additive such as Silkolene Pro FST to reduce the potential. It seems to have a reasonable success rate from what I've read (although mostly in motorbikes), my concern is more about how it would affect the ratio of the two stroke oil which is already in the fuel to any extent that matters.

http://www.opieoils.co.uk/p-809-silkolene-pro-fst-fuel-system-treatment-for-petrol-engines.aspx

[ptwizz]

While I stand to be corrected, I don't see how a fuel additive can prevent carb icing.

My understanding is that icing occurs when the pressure drop (and consequent temperature drop) through the carb causes airborne moisture to condense and freeze onto any obstruction in the flowpath, usually upstream side of the tip of the fuel jet. This changes the shape of the jet and thus changes the mixture.

Since the temperature drop, condensation and freezing occur upstream of the fuel delivery, how does a fuel additive help?

Unfortunately Silkolene's website offers no explanation.

WRT mixing, adding 2% additive to a 5% 2 stroke mix will reduce the oil content to 4.9% - so no problem there.

(5 parts oil + 95 parts petrol + 2 parts additive = 102 parts. 5 divided by 102 = 0.049 = 4.9%)

[Guest]

I remember reading years ago that it's something to do with it turning all of the water vapour present into bigger blobs of water (microscopic level I would assume)

How this helps I have no idea.

SW