Carb Iceing?

Schneider · Jan 8, 2018

I have a Case 830 i rebuilt last year and it ran well all Summer. I started it up at around 5 degrees outside and it fired right up, ran about 10 seconds and died like it ran out of fuel. kept doing this, had to play with the choke a lot and eventually can keep it running. When running it will do for for a while and then start acting like it is running out of fuel again. If i throttle down it will die. If I sit a minute it starts right up.

The fuel glass is clear. Outside of the intake manifold is iced up, makes me wonder if it is iceing up inside.

Dennis(IA) · Jan 8, 2018

Sounds like it could be icing up. Some tractors have a manifold setting for summer or winter, because the exhaust part of the manifold should
warm the intake part to prevent this. Temperature and humidity make this happen. One day it may ice up and the next day it will not.

Tony in SD · Jan 8, 2018

Most likely carb is iced. We made a cover out of an old piece of tin that covered the carb and exhaust manifold. That kept the carb from icing.
Common problem with carbarated aircraft as well. Been a long time since I?ve flown as pic but recall a carb heat lever that kept the carb from
icing when needed. I think it worked the same way taking exhaust heat to keep carb warm.

grizz02 · Jan 8, 2018

fuel would not be icing but water you have in the tank is go get 2or 3 cans of heat and dump in your tank drain float bowl and put some in it should be fine🛴

old · Jan 8, 2018

Carb icing is normal and if it does not ice then it is not working correctly. As the gas is atomized it causes things to get colder and when it is cold out well it is worse. One thing that will help you open IS to up the main jet adjustment a tad bit so as to make it run a BIT RICHER. Icing is why older cars and trucks had the tube from the manifold up to the air cleaner as it sucks in warm manifold air to stop carb icing

Ragnarok · Jan 8, 2018

There has to be a near perfect blend of humidity and air temperature for carb icing to occur...as in usually air at or slightly above freezing and enough humidity in the air that ices up the interior of the air intake/carb from some sort of 'venture effect'...but then as mentioned any water in the fuel will likely freeze at lower than freezing temperatures....in the tank..in the lines/filter and in the carb float bowel.

I've had to get vehicles inside and partly thawed so I could blow pencils of ice out of the fuel lines several times...and take the top off the carb to get the ice from the jets too. Doesn't take much water in the fuel system to block things up. Just a touch in the bottom of the carburetor will do.

The other carb icing is fairly rare on earth-bound vehicles although I have heard of it happening. It's usually heard about as a potentially deadly aviation phenomenon.

David G · Jan 8, 2018

Icing is common, but not after running 10 seconds, it should take 15-30 minutes of operation to ice.

I think you have a fuel delivery to carb problem.

Steve@Advance · Jan 8, 2018

Unless you have been able to find non-ethanol fuel, I don't think the problem is the gas.

More likely water vapor in the air freezing inside the carb, bridging across the venturi and interrupting the ability to draw fuel up the main jet.

About the only solution is to somehow draw warm air from around the exhaust to preheat the air going into the engine.

Or stay inside until it's warm!

old · Jan 8, 2018

Carb icing is very common and that is why the older cars and trucks had the air tube going down to the exhaust manifold to pull warm air intro the air cleaner. Al lis takes is a normal cool humid day and it can happen even in the summer time and is the action of atomization of the fuel. Native Americans used the same action for cooling in there cave type homes back in the 1700

roy prins · Jan 8, 2018

get a tin can that fits over your muffler -make a hole in the bottom of the can so it will fit over the top pipe -- make a hole in the side
of the can towards the the bottom of the can to receive a tin can the same size as the in take pipe -- connect it to the pipe on the tin can
-- you will suck warm air almost immediately and relieve You of the frost-- I wish I could put a picture with this because it works perfectly
Roy

David G · Jan 8, 2018

I disagree, no way a Venturi can ice up in 10 seconds.

D beatty · Jan 8, 2018

I had trouble with carb icing on farmall B and corrected it by pulling warm air from around muffler . There is no need of adjusting carb or adding anything to
fuel. It was simple to build just a piece of six inch stove pipe and pipe fits. Depending size of mufflers you may need a larger stove pipe.

gene bender · Jan 8, 2018

ethanol gas has nothing to do with the carb icing carbs have done that since the beginning nothing new about a carb icing.

docmirror · Jan 8, 2018

Very unlikely that carb ice would form in a short time running. As another poster has said, more than likely a fuel delivery problem.

Since you get it to run with the choke on, it sounds like it's running lean. Make sure you are getting fuel delivered from the tank well by taking off the fuel line, and running it to a test container. About 8GPH per 100 HP, or 4GPH per 50HP. Your fuel delivery should be well above that if it's gravity feed.

If you have good delivery to the carb, then check your mixture both at idle and under high speed. Most all carbs have mixture for idle under 1000 RPM, and a full load mixture.

Check the spark plugs, and read them for fuel mixture.

UncleTom · Jan 9, 2018

I have played with a lot of Volkswagen air cooled engines.I sometimes had them sitting on the shop floor running. I have had the carb and manifold frost up taking in 42 degree air. Then they start to run really crappy. The hot air pipes to warm the manifold were not functional. It takes heat to really cure the icing problem. Think about 42 degree air or colder and then factor in the velocity of air and wind chill it makes.

Bret4207 · Jan 9, 2018

(quoted from post at 02:38:36 01/09/18) ethanol gas has nothing to do with the carb icing carbs have done that since the beginning nothing new about a carb icing.

He's saying that non-ethanol fuels are more likely to have water in them which would lead to the classic frozen fuel we dealt with in our youth in the north.

ss55 · Jan 9, 2018

Covers along the sides of an engine can help, especially if part of the grill is also covered to reduce the air flow through the radiator. Once the tractor is warmed up, warm air from the radiator is directed back to warm the carburetor, intake manifold, and the fuel system. A little of the warm air might even make it all the way back to the operator. A heat houser helps warm the operator.

Super H Mike · Jan 9, 2018

In my experience carb icing is most prevalent a few degrees above and below freezing point.

D beatty · Jan 9, 2018

Back when we milked cows and had to use tractors in fall through spring we put heat housers on JD A and Farmall M with a burlap bag over part of grilled and it stopped the icing and heat off engine felt good.

Schneider · Jan 16, 2018

I was gone for a week.. Yesterday I played with the carb, checked the ignition and then found there was some junk in the holes where the fuel flows into the glass bowl. Problem solved.

BarnyardEngineering · Jan 16, 2018

Does applying partial or full choke allow the tractor to stay running?

You have the carburetor tuned for summer running, so it is likely too lean for the denser air in the cold, and there is no computerized fuel injection system to automatically compensate for the cold.

If so the frost on the outside of your carburetor is irrelevant. As old says, that's going to happen due to physics (see venturi effect).

This is why many gas tractors have the reputation of being "cold blooded." You have to play with the choke until they get warmed up, even after tuning them with a little richer mixture for the cold.

Carb Iceing?

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