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Liters Don’t Translate Into Horsepower

Times Staff Writer

Question: In many television ads I have watched, they talk about 2.1-liter engines or some other figure. I looked up the word in my dictionary and found that it is a liquid measure. A gallon equals 3.7853 liters. What do they mean? Will the car travel so far on this amount of gasoline or is that what the tank holds? Is this a sales gimmick? Why not measure the engine in horsepower?--C.E.S.

Answer: You shouldn’t feel badly about not understanding what is meant by liters, because automobile manufacturers do little if anything to help their customers comprehend the increasingly difficult subject of automobile mechanics. They spend millions of dollars in advertising and publicity, but don’t spend a dime on helping motorists understand how their cars work or how to take better care of their investments.

The reference to liters is a description of the size of the engine, though not necessarily to the power it generates. Engine size used to be stated in cubic inches, until Japanese manufacturers stated their sizes in liters. Now, everything is in liters, despite the obvious confusion it causes Americans who are accustomed to cubic inches. When was the last time you bought a liter of milk?

The size of an engine is determined by how much volume the pistons displace inside the cylinders when they move from the extreme top of their strokes to the extreme bottom of their strokes. This is so-called “engine displacement” and says a lot about the fuel-consuming qualities of an engine.

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Horsepower is the more important measure of engine performance, though. It tells you how much power the engine produces. Bigger engines usually produce more power, but not always. Supercharging and fuel injection have changed the relationship between size and power. And wouldn’t you know that manufacturers seldom provide horsepower information? It is almost never in the owner’s manual.

Q: I have a 1982 Honda Civic station wagon with about 80,000 miles on it. It sometimes loses power while driving or is difficult to start, as though the fuel line is blocked. A few mechanics said they believe the problem is the float in the carburetor, but there is no way to be sure. They suggest I completely rebuild the carburetor at a cost of $300. My question is whether there is a test to determine if the float is the problem.--R.L.

A: A carburetor float is one of the few moving parts in a carburetor, and problems with it can cause a number of engine problems. Gasoline is supplied to the carburetor by the fuel pump, but the pump cannot deliver precisely the correct amount of fuel at any given instant. So, all the gasoline going to the carburetor is momentarily stored in a small reservoir.

When the reservoir is full, a small float rises to the top of the chamber and closes a valve to prevent additional gasoline from entering the carburetor. It works much like the tank on a toilet with a float-and-valve system.

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If the float is cracked or has a leak, it may sink. As a result, too much gasoline enters the carburetor and can flood the engine. Another problem common with floats is that the needle valve that the float operates can become intermittently stuck open or closed.

It should be possible for a trained Honda mechanic to determine if the float is malfunctioning. On top of the carburetor, there is a device called an air vent cutoff, which vents the top of the float chamber to the intake manifold and charcoal canister. If the mechanic removes that vent valve and gasoline leaks out while the engine is running, you know you have a float problem.

If you do not have a float problem, then you are back to square one. That may be partly the reason your mechanics suggested a carburetor overhaul. Possibly they have determined that the carburetor is at fault, but are unable to isolate precisely where the problem is. You may want to seek a mechanic who is trained in Honda repair for this one.


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