Quote:
Originally Posted by jhein
So with the oil pressure safety switch, I assume cranking will give you enough oil pressure to activate the pump so it will start right up.
If you don't have any kind of shut off system and you have the ignition on, the pump turns on, then what? The pump just runs and floods the carb?
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I don’t care for the Hobb’s oil pressure switch’s on a car, there is to much delay. It is ok on something industrial where you can hold the bypass button down until it starts, PITA on a car that you start frequently. The Revolution switch that uses the tach out put is a lot better deal. That is a well thought out safely feature on an electric pump. The only down side is after the car sits very long, on an intank electric feeding a carb with 1/2” lines, the 3 second prime feature isn’t long enough. You have to cycle the key switch on an off several times. It works best with higher pressure fuel injection setup that retain line pressure better.
If the carb’s needle/seat are working correctly and the fuel pressure is set correctly the electric pumps should not flood the engine. You can pull the site plug out of a holley carb and walk off and forget the pump is running, come back an hour later and the engine will start right up. Years ago I had a Predator carb on one of my cars and the needle and seat didn’t hold and if filled a cylinder full of fuel and bent a connecting rod. I am not sure the oil safety would have caught it because you have to bypass most of them until the engine starts. That would be far less likely to have happened with the Revolution safety or a mechanical pump with the pusher pump. The electric pusher pumps I have done do not blast much fuel thru a non operating mechanical pump.