In order for your car engine to function properly, it needs just the right mix of air and fuel. But since a very, very small amount (around 10 mg) of gasoline is needed for each combustion stroke, the engine needs a special tool to control the amount of gasoline and air that gets inside. This is where the carburetor comes in. Found in older cars without a fuel injection system, this component makes sure that the air and fuel mix isn't lean (too much air) or rich (too much fuel). However, over the years, this part will need tuning or adjusting in order to keep on performing at its peak. Whenever you notice that the air-and-fuel mix is starting to get lean or rich, it's time to tune that carb. Fortunately, this maintenance task is easy. Here's what you need to do:
- Paper towels or rags
- Vise grips or pliers
Step 1: Remove the air filter.
Before you can access the carb, you need to remove first the air filter. So locate your car's air filter and remove it by unscrewing the nut and prying off the connectors that hold it in place. The exact location of this filter will depend on your car make and model so better consult your vehicle manual if you can't seem to find this component under the hood.
Step 2: Locate the carburetor's adjustment screws.
Once you have removed the filter, you'll be able to see the carb and its adjustment screws. These screws are usually found on the front part of the carb. They look like regular, flat-head screws. Check again with your vehicle manual to make sure you've found the right screws.
Step 3: Let the engine warm up.
Turn on your car engine and check the temp gauge to figure out if the engine is at its normal running temperature. Keep in mind that a lean engine will emit a pinging sound at higher RPM and with an open throttle, while a rich engine won't produce unusual sounds but will emit a strong smell.
Step 4: Adjust the carburetor screws.
Using a screwdriver, turn the screws until you find the right mixture. Start by twisting both screws counter clockwise, and then adjust them until the mixture isn't lean or rich. Listen carefully to the sounds produced by the engine as you adjust the screws since a rattling sound can signify an extremely lean mixture. Keep on twisting the screws until the engine runs smoothly.
Step 5: Reinstall all the other parts you've removed.
Once you've achieved the right air-fuel ratio, reinstall the air filter you've removed in the first step. After reinstalling everything, take your car for a test drive.
Carburetor tuning tips:
- Another way of figuring out your car engine's air-fuel ratio is by using a digital meter. This ingenious device is widely available at many auto parts stores and is easy to use. Some types can even be linked to your computer so you could conveniently view the data.
- Since you'll be working with the carburetor (a fuel source), make sure you're working in a well-ventilated area.