I made my own for my dragster for starting and driving around. I used the facet pump and a nitrous plate and an orifice in the pump outlet line. Mine is wire so that 12 volts is available to the solenoid and pump only when the ignition is on and the oil pressure is above the switch setting (7psi). I activate it through a toggle switch so I can turn the fule on and off. The only issue is forgetting to turn it off when I pull the main pump shut off lever to the on position.

During the summer months I run alcohol in the primer and use a .041 orifice in the line to a nitrous plate. In the late September and October months I use gasoline and a .031 orifice. On alcohol, in the summer; the .041 orifice will generally produce a 14 to 15:1 (reading is on the gasoline scale) air fuel ratio and usually will build heat just fine. I measure the air/fuel ratio in tube #5 on a full length header about 3 inches from the flange.

My routine is to flip the ignition on, flip the primer on, wait about 5 seconds then hit the starter, and once the engine starts pull the main fuel supply on and shut the primer switch off. If I am just moving up the lanes I will do the same, except I would not pull the main pump on.

bob