ice cold manifold

bill from massachusetts · Jun 6, 2012

does anybody know why the manifold on my 1956 international 300 utilty with a c-169 four cylinder gas engine,when started the bottom of the manifold where the top of the carburetor meets the manifold turns cold and wet even after the tractor been runing for awhile.Its a IH 1/1/4 updraft type carb.I'am puzzled,any help would be much appreciated.

FC Andy · Jun 6, 2012

There are a few guys that can explain this a little better than I, The cool comes from the heat that is removed from the air to vaporize the gasoline, and the moisture is moisture from the outside air condensing on the manifold and carburetor. -Andy

uncle henry · Jun 6, 2012

i've got a super mta that's been doing the same thing about four years

Bob M · Jun 6, 2012

That's perfectly normal! It is the result of gas evaporating and cooling the fuel mixture in the low pressure area above the throttle plate. The external condensation is most evident when the relative humidity is high.

Incidentally in cool, humid weather (temps between about 32 and 50) you can get frost forming. The frost will also form INSIDE the carb (carb icing) and give all manner of running problems until it thaws out.

robgIN · Jun 6, 2012

google latent heat of vaporization.

old · Jun 6, 2012

That is just as it should be. As the fuel is atomized it turns to vapor and that in turn causes things to cool down way down in fact. The Indians way back when used the same thing to be able to have things cold in the middle of the summer in many of the south west states of the U.S.A. As things evaporate they cause things to cool down and that is how the carb system on all gas engines work

bill from massachusetts · Jun 6, 2012

thanks for your help

ice cold manifold

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