I have an older boat which has an electric gasoline pump wired so that for safety reasons the pump is only on when the engine has oil pressure and if the oil pressure drops it turns off the pump.
The pump is controlled by a standard bosch type 5 pin automotive relay.
The problem is with the boat motor at hot idle, the oil pressure fluctuates up and down rapidly. from perhaps 5 to 15 PSI on the manual gauge.
This causes the oil pressure switch to open and close which causes the relay to also open and close rapidly which causes the pump to turn on and off and the pump indicator run light to flash and the buzzer beeps on and off.
I put a restriction in the oil line feed to the pressure switch which helps a little.
How can I electrically keep the relay on for the short time the oil pressure drops ?
This is a wiring diagram I found on the web showing the basic idea of how the boat pump works.
Mine has an added manual priming button I added to show the entire existing circuit.
The pump is controlled by a standard bosch type 5 pin automotive relay.
The problem is with the boat motor at hot idle, the oil pressure fluctuates up and down rapidly. from perhaps 5 to 15 PSI on the manual gauge.
This causes the oil pressure switch to open and close which causes the relay to also open and close rapidly which causes the pump to turn on and off and the pump indicator run light to flash and the buzzer beeps on and off.
I put a restriction in the oil line feed to the pressure switch which helps a little.
How can I electrically keep the relay on for the short time the oil pressure drops ?
This is a wiring diagram I found on the web showing the basic idea of how the boat pump works.
Mine has an added manual priming button I added to show the entire existing circuit.