Cold Carburetor?

[Mojo^]

I have a 1997 Johnson 25 hp. 2-stroke. Tonight while trouble shooting an entirely different problem I noticed that the carburetor and intake manifold was quite cold to the touch. So cold in fact that moisture began to condensate on them. The ambient temp. was around 80 with 35% humidity. What would cause this?

 

[DJ]

Re: Cold Carburetor?

Normal.

A carburetor is a venturi which speeds up air flow. When you do that it chills the air and condenses the moisture in the air.

 

[Silvertip]

Re: Cold Carburetor?

Ever heard of the term "carburetor ice" as it relates to automobiles and airplanes. If you've never driven a carbureted car up here in the tundra in the winter you probably would never experience it. But as DJ says, air passing through a restriction speeds up the flow thus creating a cooling effect.

 

[Mojo^]

Re: Cold Carburetor?

Fascinating. Here in the southeast, I've never heard of carburetor ice or noticed this phenomenon before.

 

[DJ]

Re: Cold Carburetor?

Fascinating. Here in the southeast, I've never heard of carburetor ice or noticed this phenomenon before.

It was very common in old carbureted cars, especially in high humidity. In a vehicle it can create a "stumble" on acceleration which is annoying. In an airplane it's terrifying!

 

[wifisher]

Re: Cold Carburetor?

Just think of it as a redneck A/C unit.


Don't airplanes have carb heaters to keep them from freezing?

 

[DJ]

Re: Cold Carburetor?

Don't airplanes have carb heaters to keep them from freezing?

Yup, if you remember to use it.