ice on carb

How do I keep the manifold and Carb from icing up in the winter? Love the cold air in summer, just don't need that much now cutting firewood with the 400. Thanks

Is it affecting how it runs? The venturi portion of these carbs always will "ice up", even in warm weather. If the ice you are refering to is on the outside of the carb, there is no harm, in fact, it indicates your carb is "breathing" normally.

If you have internal icing, you have water in the fuel. Dry gas or similar will correct that. Plus, drain your fuel tank completely and keep the moisture out of it by keeping it relatively full (or in a heated building).

I thought that may be making it too cold. If ice on the outside
is desirable, mine is desirable. Does anybody make s heater
housing for those tractors any more? I have a feeling my
summer mods are not liking below freezing.

I see them on the "for sale" portion of this site and on eBay every once in awhile. Grab hold of your wallet when you see the price........sticker shock is common.

External icing is a common thing nothing new it even happens in warmer weather.

Icing is normal in 20-45 degree weather. The icing on the outside does not hurt anything, icing on the inside will cause it to stumble.

My MH44 ices real bad and will stumble up until the manifold warms enough to melt the ice on the inside.

Half expected that was the case with price.

You could make up a system that pulls warm air off muffler.

I used to have an older VW Beetle that the carb would ice until it choked it to death. Had to route the heater hose from the right bank to the carb, I guess you could call it a pre-heater, worked great, just no heat on the wife"s side of the car.

I would hang a towel from the radiator to the carb.That bit of warm air is all it took to prevent/get of ice.

There must be something that can be done to keep the carbs from icing up. I've driven IH gas tractors for over 30 years, both 4-cylinder and newer 6-cylinder. Never even seen a flake of frost.

I don't recall us doing anything special. Heck, until we started dragging old tractors home I don't think we ever pulled a carburetor off a tractor.

Must be a regional thing. Ive never had a carb on an
IH tractor ice up either. Maybe a little sweat in
the spring or fall, but even thats minimal.

John, I figured regional too, maybe humid climates, but you shot my theory down. I'm just 25 miles from you and my SMTA was icing back in the summer when it was 90 degrees out. It was just riding around, not working, so maybe getting more heat in the engine would have melted it.

There should be a nail hole under the manifold pointing down to carb. this take's a little time to warmup. It work's better if there is a heathauser on it so you want see the ice,ha.Beside's the blanket will warm the carb.

Where are you from?

Pelzer.

Ok, let me help out here a bit. The action of the carb is to vaporize the fuel. So, let's talk about the physics behind that. Boyle's Ideal Gas law states PV=NRT. Translation: Pressure x Volume = Number of moles of gas x Universal Gas Constant x Tempurature in Kelvin. so, to keep things a little simpler, Pressure and volume are directly proportional to the tempurature if you consider that Moles and the UGC are constant.

So, let's put this into even simpler terms. If you change the volume (ie. going through the venturi) the pressure and/or the temperature MUST change. Now, add on top of that the heat capacity of gasoline, which is how much energy (heat) it needs to absorb to vaporize. So, you lower the pressure (vacuum), increase the velocity (vaporize and heat capacity of vaporization) and you absolutely lower the tempurature of the carb. Can't change that fact. The tempurature drop can be dramatic. Think about when you drain your air compressors. Water can turn to ice because of the pressure drop and the associated tempurature drop.

Last factor, how much heat is being transferred from the manifold. If you have a thick gasket between the carb and the manifold, heat is NOT being transferred at a high rate. Add it all up.

Bottom line, depending upon a number of factors, including abient humidity, your carb CAN ice on the outside. If you are getting ice on the inside, likely problem is watger in the fuel. I can go into more detail if anyone wishes, but this is basic physics/chemistry. almost all my carbs ice, except for the F12/F14 (sits on top of hot manifold), and the Regular (sits on front of a hot manifold and is brass). I could make snow cones off my F-20. The cub has frost on it all the time. Heck, I started the KB5 the other day, and it's carb iced up. Don't worry about it unless you are having ice inside the carb, then it's a different problem......

Sorry previous post was long winded. Here are basic examples. Pour some acetone or ether on your hand. It evaporates and cools your hand because it absorbed heat from your hand to vaporize the liquid. Same principle when vaporizing gasoline.

2nd item. As stated in previous post, when you drain the water out of your air compressor, it can freeze up and create ice, which causes the water not to fully drain until it thaws. In a carb, the air flowing through the venturi is accelerated and the volume is reduced. After it exits the venturi, with the gaoline DROPLETS (not vapor yet), the volume is dramatically increased when it hits the intake port and has the same velocity.

couple the heat of vaporization (heat capacity) and the decrease in pressure exiting the venturi, tempurature drops like a rock. now, after the tractor has been running and everything is up to operating temp, icing tends not to be a problem. But that is all predicated on being at operating temperature.

(quoted from post at 16:47:28 01/17/13) Sorry previous post was long winded. Here are basic examples. Pour some acetone or ether on your hand. It evaporates and cools your hand because it absorbed heat from your hand to vaporize the liquid. Same principle when vaporizing gasoline.

2nd item. As stated in previous post, when you drain the water out of your air compressor, it can freeze up and create ice, which causes the water not to fully drain until it thaws. In a carb, the air flowing through the venturi is accelerated and the volume is reduced. After it exits the venturi, with the gaoline DROPLETS (not vapor yet), the volume is dramatically increased when it hits the intake port and has the same velocity.

couple the heat of vaporization (heat capacity) and the decrease in pressure exiting the venturi, tempurature drops like a rock. now, after the tractor has been running and everything is up to operating temp, icing tends not to be a problem. But that is all predicated on being at operating temperature.

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Listen to Tom

There is a heat houser available for your tractor, this site won't let me post a link to it. Type in the word "Valu' and then "bilt" and search for item 1212430 Called a heater cab $265