have a 300 I6 in an older 1980 travel van (great van)..... having a problem with the base of the carb. icing up in 40F. temp. and lower. As a result the motor powers out to the point of stalling......Any suggesting as to what the problem may be......thanks for any help.

 

Well, you didn't perhaps put on headers recently, thus removing the heat from the heat riser to the intake manifold?

If you are running stock, I think they still have a heat riser in the 1980 setup. Maybe the exhaust gas diverter (little flapper with a metal coil and a weight) maybe froze up in the position that directs all the gases out and does not allow enough heat to rise up around the intake manifold.

Possible the 1980 setup used a warm air "stove" to the air cleaner -- I don't know for sure, especially for a van. But in the stove setup, there is a sheetmetal shroud over the exhaust manifold which collects some warm air for a duct up to the horn of the aircleaner. There is a thermally activated flapper that sends warmed air to the carb in cool conditions. It may be shot or stuck closed.

Hope one or the other of the above helps you.

 

I have an 81 f150 and the carb was icing up on me at that temp and soometimes 50 degree temps. I found out that it was sucking air under the carb and that little space plate. I replaced teh gaskets and its fixed

 

thanks for the info. I had opened up the exhaust and I guess maybe to much also put a rebuilt carb on......will check all coments thanks again......