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Christopher Mikesell 10-28-2012 09:42:48 76.226.201.14 Report to Moderator

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. [Reply]   [No Email]