Case DC4 carb freezing

[jvw1955]

We have a 1955 Case DC4 which is still used on a regular basis fr PTO work, raking etc. But it is getting very hard to use on colder days, as the pipe from the carb freezes shortly after starting. Any solution to this? It starts very easily, I don't even use a battery, just a couple of cranks.
 

[Christopher Mikesell]

This is called carbrator icing. It happens on cold damp days when there is a lot of moisture in the air. The main reason that it happens is that the carbrator venturi increases the velocity of the air and drops the pressure to draw the fuel. This causes water to condense out of the air and freeze. This problem is exacerbated by the increaseing use of ethanol in fuel (especially during the winter months, and especially in southern california and the surrounding states). Ethanol has a much greater heat of vaporization than gasoline, so it sucks up a lot more heat as it vaporizes. The solution is to run the tractor at idle until the intake manifold warms up, to insulate the manifold so that it looses less heat to the outside air, or to run gasoline without ethanol. You could also take off the muffler and make an exhaust pipe that blows right onto the manifold above the carbrator. Carbrator icing is a common problem with piston engined aircaft when the conditions are right, and aircraft have a carb heat system for dealing with the problem.
 

[pete 23]

Often times, if you shut the tractor down after it is warm and iced up, the heat from engine will thaw it out and keep manifold warm enough upon restart to not bother again until next cold start up. What some guys do, not necessarily on that model tractor but all same principle, is to build a stove around the muffler, hook a tube to it and run it into air cleaner intake. This brings dry, warm air in but no exhaust with it. Same thing cars did with the air intake on carbureted engines only they had a thermostatic control on air cleaner to by pass it when air temp was warmer.
 

[dcz3]

I have a DC that does the same thing when I use it for snow removal and yes I do run ethanol. I bunge cord a piece of cardboard on the carb side problem solved!
 

[Moline_guy]

As far back as I can remember, my uncle had a license plate wired to the manifold above the carb to prevent this very thing, never seemed to bother with that on.
 

[rusty6]

A DC4 that starts in winter? I can only dream about that. Mine won't start on the hottest day of summer if it pulled by another tractor. I call it my "pull start tractor". Carburetor icing is a problem on most of my gas engines but as stated by others, just shut down for a few minutes to let the engine heat up the intake manifold and that usually clears it up and keeps it ice free on my Cockshutt 40, IH Loadstar, Olds engined pickup truck, etc.
 

[jvw1955]

Thanks for all the responses, I was thinking maybe the carb just needed adjusted, since it seems to be worse in recent years, but that may be the new blends of gas instead, as mentioned. I'll try the cardboard first, that seems like the easiest route.
 

[mEl]