Preventing Carb ice by adding ethanol

Sun, Jan 17 2016 03:56am CST 1
Rob Mus
Rob Mus
8 Posts
Hello website,
Here in Denmark they sell "karborator Vaesks", its a mixture that you add to your gasoline and it should prevent carb ice, and removes condensate from the tank.

It contains Ethanol,
Now my question, should I use this on my trike with a Rotax 503, (yes carb heat is better, but this is a quicker solution.

Who has some experience with this?
Sun, Jan 17 2016 09:53am CST 2
Clemens West
Clemens West
14 Posts
Hi,
I use 1% Isopropanol in my 4-Stroke Briggs&Stratton without any problems. It is adviced in my owners manual to use it below 4 degrees Celcius and high humidity (they say use between 0,5 -1%). Guess it would work on a 2-Stroke as well.

Mon, Jan 18 2016 09:09pm CST 3
Jim Davidson
Jim Davidson
12 Posts
Carb ice comes from moisture in the air being sucked into the engine through the carburator. It does not come from the fuel being consumed. Carb ice is caused by the "venturi effect". Google it.
Gas line antifreeze is another thing and usually is nothing more than methyl hydrate. Methyl hydrate mixes with your fuel and displaces the water in it. As you use up the gas in your gas tank, air flows in, and often that air is heavy with moisture, even if the air temperature is not very high. When the tank cools afterward, the moisture in this air will condense onto the cool sides of the tank (think how much dew you sometimes find all over your car on a cool summer morning). This water then runs down to the bottom of the tank, since water is more dense than gasoline and won't mix with it. By fall, especially in humid climates, there can be a cup or so of water rolling around in the bottom of your gas tank. When the temperature drops below freezing, that water turns into something like snow mixed with ice crystals. Before it freezes, it can get caught in the intake to your fuel pump and even work its way up front to your fuel filter, causing low fuel pressure and fuel starvation.

Tue, Jan 19 2016 08:08am CST 4
Jackye  Reynolds
Jackye Reynolds
18 Posts
I've only had one experience with carb ice with a Rotax 447- 2 stroke on a fixed wing ultralight. I have thought it would be very difficult to develop carb icing in a 2 stroke air cooled pusher aircraft, but I have modified my flying procedures since my one encounter with it. I will avoid a long power off descent, during which I will sysematically rev the throttle (or some call it "burping") for a few seconds every 10 to 15 seconds. My first and only encounter with carb icing was on a late Summer evening flight and I was testing my "dead stick" skills in my new to me "free air cooled" Weedhopper. These planes are not known to have good glide ratios, and fortunately I had set up my "long final" with plenty of altitude. However I barely "squeaked it in" over the highway before the threshold. I thought the engine was running, because the prop was turning, but every time I increased the throttle, it would just shudder and "bog"!
I had no power from the engine as I landed, and the prop stoppped on the roll out. I had felt some water droplets on my arm and saw a few on the windshield. I got out of the plane and saw frost quickly melting from the exterior of the bing carb, and manifold, after the rubber boot. I didn't have a camera to document the occurrence but had been told "it never happens on a 2 stroke!"
Tue, Jan 19 2016 09:19am CST 5
Ted  Bailey
Ted Bailey
14 Posts
Carb ice forms from dew point and air temps being too close together.
I don't fly when the temps are closer than 8 degrees to dew point. Simple!
Thu, Jan 21 2016 11:19pm CST 6
monty stone
monty stone
63 Posts
hi guys, yep carb ice CAN occur on two stroke engines, see my blog 'carb ice' nov4 2012, monty
Fri, Jan 22 2016 01:45pm CST 7
Clemens West
Clemens West
14 Posts
Mon, Feb 22 2016 02:24pm CST 8
Miracle Pie
Miracle Pie
7 Posts
Ethanol is hydrophyllic - water loving. It attracts moisture from the air which can/will condense in the fuel system and freeze at altitude. That is why aviation fuel contains no ethanol, and why one should never run E pump gas in any flying machine. Fuel system freeze-up is not the same as carburetor icing, but nonetheless I cringe when I hear of someone running ethanol fuel in trikes. BTW, I speak from the persepective of 35 years in the US wholesale petroluem industry.

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