- Do It Yourself Auto Repair
Replace a Fuel Filter - Common
Fuel filters come in a wide variety now-a-days. Some of the varieties include:
- Inside the carburetor inlet hose (found in Holly carburetors)
- In-line at the fuel inlet hose before the carburetor.
- In-line usually below the drivers door on the undercarriage.
- At the fuel tank outlet.
Then there are the performance choices:
- Standard Performance
- Small Engine
- High Performance
- Marine Use
If that isn't enough; there are several fuel filter manufacturers to choose from:
- Mr. Gasket
- and of course Holley
Why is the Fuel Filter Important
If you look at the carburetor in your vehicle it works very much like our heart works. Our heart pumps blood and oxygen through a network of ventricles and veins to make our body run. The carburetor meters fuel and oxygen through a network of venturi, jets and hoses to "nourish" the engine so it can run. We humans have a filter to clean our blood, the liver. Like the human body, carburetors have a filter as well, a fuel filter.
The fuel filter collects debris that would otherwise pass through into the carburetor. This debris can cause blockage and build-up. Since debris is heavier than fuel, it settles at the bottom of the fuel tank. If you run your gas tank down to empty, a few times a year, your fuel filter is working overtime. It will collect more debris than if it never, or rarely, ran low.
A clogged fuel filter will restrict the flow of fuel and you will notice a lack of power and or the engine will stall.
A good rule of thumb for replacing the fuel filter is every 30,000 miles or once a year. If you rarely drive your car then, of course, less often would be appropriate for you.
Inline or At the Carburetor
Standard or High Performance
4 x 4, Dune Buggy, Quads
Inline AND at the Carburetor
In the Carburetor
Marine High Performance
How to Change the Filter - In the Carburetor
Changing the fuel filter in the carburetor and at the carburetor are extremely similar. At the carburetor the fuel filter will be in the larger attachment just before the carburetor (see photo) whereas in the carburetor will not have the large attachment. It will be the hose into the carburetor nut. For these fuel filters:
- Make sure the engine is off and cool.
- Remove the negative wire from the battery to avoid an accidental start.
- Place an old rag under the nut to catch any fuel that may spill out.
- At the carburetor inlet there is a metal hose that goes into a nut that goes into another, larger nut. It is the larger nut that must be removed to access the fuel filter. (see photo)
- Place a wrench on the nut and turn counterclockwise. If it is a fuel filter inside the carburetor place a wrench on the carburetor nut and one on the inlet nut. This will help prevent bending or breaking the hose. Turn the nut counter-clockwise.
- When the nut is removed the fuel filter is right there and should come out. You may need to grasp it with your fingers to remove it.
- Put the new filter in the carburetor hole.
- Screw the nut back into the carburetor.
- Start the car and check for leaks.
At Carburetor Fuel Filter RemovalClick thumbnail to view full-size
Inline or at the Tank Fuel Filters
Fuel filters inline or at the tank are similar as the at and in the carburetor type. The inline on most vehicles is located below and under the drivers side door frame. The inline at the tank is further bank nearer to the gas tank if not at the gas tank. Follow the fuel line to find these fuel filters if not at the specified locations. To change these types:
- Locate the filter along the fuel line.
- Place a catch-all container below the filter to catch any gas that may spill.
- Remove the clamp holding the filter in place.
- Using pliers pinch the hose clamps to release the hose on each side. If the fuel filter is the screw on type use two wrenches like the at carburetor type to avoid bent or broken hose lines.
- Remove the old filter.
- Place the new filter in position the correct direction. There will be an arrow on the filter indicating the direction of flow.
- Screw the nuts into the new filter or press the hoses on the new filter and reattach the hose clamps.
- Reattach the restraining clamp.
- Start the car and check for leaks.