Carb icing

[KE4AVB]

Believe or not I have Kawasaki FX751V-DS04 that has carburetor developing ice @ 90F and 90+% humidity. Engine hard to start right after shut down. Sit a few minutes and start right up. Carburetor is cold to the touch and is sweating on it exterior.

Not a coil, plug or carburetor problem. Has new coils and plugs. And carburetor has been rebuilt after a suspected fuel leakage.

[Skywatcher]

Hi KE4

The Bernoulli principle can have some unexpected effects on carburetors. I remember our 2nd year technical school instructor for heavy duty mechanics telling us that carburetor icing can happen at temperatures way above freezing if the humidity and other conditions are just right. All the best,

Sky

[KE4AVB]

Understand the theory. I personally experience it with temps in the 70's many years ago in the Piper Tomahawk I was flying. It took over 5 minutes for the carburetor to thaw even with carb heat turned on. I was over a high congested area with no where to land. When I finally had the airport in site engine recover. I was getting pretty low as the engine lost a lot of hp. With the engine recovered I was able to get back on the proper glide slope for a normal landing.

Now I understand why all practice the instructors put me through on pretend problems. It so things are second nature with you run into these problems.

But this freezing at 90+ was a surprise. I figured it out to be the extreme humidity that I was mowing in as it came a cloudburst about 15 fifteen minutes later.