How a carburetor is supposed to work

Dear Car Talk

Dear Car Talk | Feb 01, 1991

Dear Tom and Ray:

I have a 1986 Plymouth Voyager with the 2.6 liter Mitsubishi engine. The car has 70,000 miles on it and is in very good condition. It runs great and fulfills my needs perfectly. There is one annoying feature that I would like to eliminate if possible. When cold, it starts in the fast idle mode, 1300 RPM. After it warms up for about three minutes, the idle comes down to 600 RPM. I don't like the idea of putting the cold transmission in gear at 1300 RPM, and would expect to be able to reduce the idle speed by tapping the accelerator pedal. But it doesn't work, and a Plymouth mechanic said it isn't supposed to work. Could this be true?

RAY: It is true, Carroll. The Plymouth mechanic is right. This engine has an unusual carburetor made by a company called Mikuni. This carburetor was used primarily on Mitsubishi-made engines, and they all behave the same way.

TOM: It's a wonderful carburetor, but it has one quirk; you can't kick it down. When it's good and ready to come down, it comes down.

RAY: So you have two choices, Carroll. You can buy a copy of War and Peace and read a few pages every morning while you wait for the idle speed to come down. At the rate of three minutes a day, you should have the book finished in time for the next census.

TOM: The other option is to buy War and Peace as a "book on tape," and just drive away in the morning. The truth is, you won't do any damage by putting it in gear at 1300 RPM. In fact, it's the best thing for all involved; the car, the environment, and your boss whose waiting for you impatiently at that 7:30 AM meeting.

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