Ethanol or E85 Primer System
with Carbed Engines
Ethanol absorbs moisture when exposed to the air, and also starts harder as the temperature goes below 45 degrees. When parking a E85 carbed engine, the fuel in the carb is exposed to the air from the bowl vent tubes. To address both of these, I decided to add a small fuel cell and pump, and be able to fill the carb with gas as needed.
With EFI, the above are not much of a concern since the fuel in the injectors are not exposed to the air, the fuel tank is sealed and the air temperature sensor allows the computer to richen the air/fuel mixture as the temperature gets colder.
When getting ready to park the car, I flip off the main fuel pump, and when the engine stumbles, I turn on the small gas pump. then drive into the garage. This fills the carb with gas to prevent moisture being pulled into the carb, and also makes starting the next time very easy with it starting on gas. With the carb jetted and adjusted for E85, it will run rich just like it has a choke. When it is running, I pull it out of the garage and let it run for 1-2 minutes, then turn off the gas pump, and switch on the main pump.
To prevent moisture from being pulled into the fuel cell, I put a ball valve on the vent line. When parking it for the day, the ball valve is closed.
A filter is installed to prevent bugs from nesting in the vent.