Cars and Carbs

No, not carbohydrates. Carburetors. All cars used to have them. Now, thanks to EPA standards for fuel economy and emissions, car makers use fuel injectors instead of carburetors.

I realize many of my readers don’t know a carburetor from a crabapple, and that’s okay. The carburetor is a device that blends air and fuel to provide a precise mixture to burn in the engine. But it’s really just the McGuffin in this post. Hitchcock would understand. The story is the thing.

This story started with a mischievous teenager (probably) who dumped a quart of milk into the gas tank of my dad’s Buick Electra. This was before gas filler door locks became common on cars. Where did he get the milk? Well, milk in glass bottles was once delivered to many people’s front porches early in the morning. Our house was no exception.

The vandal left the bottle sticking out of the fuel filler tube, which was located behind the rear license plate. When he saw the empty bottle, dad realized what had happened. Rather than start the car and risk sucking contaminated fuel into the fuel line, dad had the car towed to a service station so the fuel tank could be flushed. Not only did a quart of milk contain almost a quart of water, but the milk solids were converted to a solid, brownish residue when the milk hit the gasoline.

The service station did a poor job of flushing the tank. A lot of milk residue remained in the tank and got into the fuel line. When the contaminated fuel got to the fuel filter in the engine compartment, it stopped up the filter and the engine stalled. When that happened, someone (dad or me) would have to open the fuel filter, remove and clean the filter element, and replace the element back inside the fuel filter.

One day news came of my dad’s brother’s death. We drove from central Virginia to St. Petersburg, Florida to attend the funeral. The morning of the funeral I prepared the car for the day’s events. I raised the hood, disassembled the fuel filter, cleaned out the brown milk residue that had accumulated during the trip, and reassembled the filter. Unbeknownst to me, I got the filter element slightly misaligned in the filter body with the result that contaminated fuel could get past the filter and enter the carburetor.

Carburetors are a wonder of design and precision. The inside of a carburetor has small passageways to allow fuel and air to flow to various chambers; everything works off air pressure. Fuel is sucked through “jets” which are small, metal plugs with tiny, precisely drilled holes through them. There are idle jets, off-idle jets, high speed jets. There are cams and fuel bowls and mixture screws and all kinds of ways to screw up a carburetor if anything other than fuel gets into it. A small engine uses a one-barrel carburetor, so called because it has one “venturi” containing a choke plate, throttle plate, and fuel jets. Larger engines use a two-barrel carburetor, which is like having two carburetors in one assembly. Dad’s Buick Electra with its large V8 engine required a four-barrel carburetor. It was like having 4 carburetors fused into one assembly.

It was a sunny day when my mom, my dad, my younger brother Ken, and I got into the Buick Electra and headed for the funeral. Dad, Ken, and I wore suits and ties, of course. This was olden times and showing respect for the deceased’s family was the custom of the day. We were driving down a busy highway when the engine stalled. We knew immediately what the problem was.

The Buick coasted to a stop on the highway shoulder. We cleaned the fuel filter element but the car wouldn’t start, and we realized that the carburetor was plugged up with milk residue that had gotten past the fuel filter. Dad went nowhere without his toolbox in the trunk, so we got out tools and started the process of removing the carburetor from the intake manifold. We disconnected the fuel line, rubber vacuum hoses, the throttle linkage. We removed the carburetor to the side of the road. We disassembled that 4-barrel carburetor right there on that busy highway under a hot, central Florida sun with traffic passing by us a few feet away. We cleaned out the carburetor’s fuel bowl and all the little passages. We reassembled the carburetor and installed it onto the intake manifold and hooked up the vacuum lines and fuel line and throttle linkage. We started up the car and drove to the funeral. We got there on time.

When I was young it seemed like that kind of thing happened all the time. You just pushed forward. You did the next thing. You didn’t complain. You did what you had to do.

That wasn’t the last carburetor I worked on. If I thought my car was sluggish because of a dirty carburetor, I didn’t hesitate to disassemble the carburetor and soak it in carburetor cleaner. After you’ve disassembled, cleaned, and reassembled a 4-barrel carburetor beside a busy highway while wearing a suit and tie under a hot sun, carburetors don’t intimidate you.