460 carb icing

I have a couple of 460's and a 656 all gas and all seem to have the same issue. Whenever it is cold out or cool and damp the carbs seem to frost up making the engines run rough until they warm up. They are of course fine all summer but the other morning when it about 50 degrees out it was running rough and sure enough the carb had frost on it again. Is this a common problem in the north and is there any solution to it thanks

this has happened since the first carb was invented. temp and RH just rite and it happens you can make a shield to "warm" the carb but as the weather changes so does the problem

That is fact of life and how a carb works and if it didn't do that the carb would not work. It is caused by atomizing of the gas as it goes into the manifold. That is why cars and trucks back in the day hot the air tube off the exhaust manifold to suck in warm air or they too would do that

A "stove" can be made to fit around the muffler, and have a stainless steel spiral hose to the air intake tube. The image is from 2007 right here on YT. It can be made far more elegant. Jim

Thanks that's an interesting solution but it would solve the problem. I had forgotten some of my older cars had a tube to draw warm air from the exhaust manifold. I'm sure I could make something just as elegant but if it works it works

Look at the old Oliver's they had side curtain which helped a whole lot with carb icing a simple sheet of steel on the carb side will stop icing

I?m surprised Jim didn?t mention this, but all the tractors you mentioned have what is commonly called a heat riser. It is a valve or diverter in the exhaust manifold that if operating correctly directs hot exhaust towards the section of the intake manifold above the carburetor. Although it will not stop the carb icing you are referring to on a cold engine it will help warm up the intake manifold at point the carb mounts thus transferring heat to the carb and reducing the trouble you are experiencing. On the parts page in the link number 5 is a coiled thermal spring you should see on shaft 9 sticking out of the exhaust manifold above the carb. Number 8 the valve mounts on the shaft. I can?t tell you the exact operation but I believe when cool the spring causes the valve to move more vertical to direct exhaust down towards the manifold. The as the manifold heat warms the thermal spring tension relaxes and lets the weight 10 move the valve more horizontal as shown closing off the exhaust from the intake manifold. So mainly making sure the shaft 9 moves and is free and the thermal spring is in tact will be things to check to minimize the poor engine response you see in cold weather. That said these IH 6 cylinder engines tend to have reputation of being ...cold blooded...
IH parts pages

Look at the old Oliver's they had side curtain which helped a whole lot with carb icing a simple sheet of steel on the carb side will stop icing

Thanks, I remember the springs on the manifolds but never knew what they were for. I'm pretty sure that they are most likely rusted up so I will take a look and see if I can get it working. I only use one tractor in the winter for moving hay so I'll start with that one.