How to Change a Gasoline Carburetor to Alcohol
- 1). Buy a spare carburetor identical to the one in your gasoline powered car. Work on the second carburetor. If you experience an unexpected problem, you will still be able to drive your car.
- 2). Disassemble the spare carburetor. Use the exploded diagram in a carburetor overhaul kit as a guide.
- 3). Determine the exact diameter of the metering jets. Typically, gasoline carburetors have both idle, or low speed, jets and main jets. The diameter may be in the shop manual for your car. You can also contact the manufacturer of your carburetor, or you can use an air gauge to measure the exact size of each jet. Air gauges precisely measure air flow volumes and back pressure to reliably measure the exact size of carburetor jets. If you do not own an air gauge, find a machine shop that will measure the jets for you.
- 4). Replace the jets. Ethanol combustion requires jets that are 40 percent larger than are required for alcohol combustion. Replace the old jets in your carburetor with new ones that are 40 percent larger in diameter. It is possible to increase the diameter of your existing jets by using a drill of the proper size and a drill press.
- 5). Modify the float assembly. Ethanol is heavier and denser than gasoline, so to maintain proper fuel flow your float must be 10 percent heavier to work properly with ethanol. Some carburetors -- Holleys, for example -- may also require you to replace the 30cc accelerator pump with a 50cc accelerator pump. Weigh your float on a kitchen scale. Increase the weight of the float by 10 percent by evenly adding solder to the top of the float.
- 6). Reassemble the carburetor using the parts and following the instructions in the overhaul kit.
- 7). Remove the carburetor installed in your car. Remove the air filter. Take photographs of your installed carburetor for reference. Unbolt the carburetor. Set all small fasteners on a clean rag on a bench away from your work. Put a clean rag in the intake manifold after you remove the carburetor.
- 8). Install the modified carburetor using the photographs as a reference.
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