I’m still driving an old car. It uses a carburetor for the fuel and air mixture. Just recently, I encountered a problem with my carburetor which resulted from the improper installation of my air filter. I replaced the stock air filter with an aftermarket sports filter so all it needs is frequent cleaning. It looks like a plate which sandwiches the filter as you can see in the picture of my car’s engine compartment. As with most carburetor air intake systems, it uses a wing nut to secure the filter to the carburetor.
We were just about to leave for a long drive last week when around 2 kilometers from our home, I saw the engine RPM (revolutions per minute) go up without stepping on the gas pedal. I immediately noticed that and I initially thought that it’s a problem with the carburetor. I was correct. When I opened the hood of my car, my air filter’s wing nut wasn’t there anymore and the air filter is about to fall off from the hinge that secures it to the carburetor. Had I continued to drive the car, it could have fallen off the carburetor causing severe damage to the other parts of the engine. It confirmed that the problem is with the carburetor and the reason was the air filter.
A few weeks prior to that, we had a tune-up and I remember the mechanic cleaning the air filter that day. He most likely did not secure the wing nut properly, leaving it loose and causing it to fall off. I should have checked it afterward to make sure it was tightly screwed, but it was too late.
So, I used a regular nut to secure the air filter and drove the car back home very carefully. I had to adjust my foot on the clutch in order to bring down the rpm especially during stops. Two days after that, I brought the car to a car service center and the senior mechanic there told me that the carburetor is clogged. He choked the carburetor by removing the air filter then revving the engine while covering the carburetor with his hand. Within 5 minutes, he fixed the carburetor and it went back to normal rpm. Had it not worked, I would have needed a repair kit to fix the carburetor or worse, replace the entire carburetor completely.
In addition to the sloppy work of the previous mechanic who tuned up my car, I was lax in inspecting my vehicle. The good thing is that I immediately saw the problem and the repair was not expensive. All I had to pay for was the labor.
Most of the new cars, if not all, have fuel injection systems that mix air and fuel for the engine and old, classic or vintage cars usually have carburetors. The air intake system is vital to its function since it is where the air comes in and where it is being filtered. And based from my experience, improper installation of the air intake system can cause damage to the fuel injection system, the carburetor or even the engine.
Always check your air intake system and see if it is properly and securely connected. Observe your idle rpm to see if it is in the normal range. The senior mechanic told me that the ideal setting should be just around 850 to 900 revolutions per minute. If it goes up significantly on its own, have it checked immediately. Not only will you waste gas but it might cause severe damage to your engine.
Derio – Mechanic
Dallas Service Center
Tomas Morato, Quezon City, Philippines
Wikipedia – Fuel Injection
Wikipedia – Carburetor