92 4.3 mercruiser oil pressure question

[bdubs217]

My winter project is done I have recently completely rebuilt my 92 mercruiser 4.3 it runs great but my oil pressure guage is reading 0 psi and I know this is not true. after going through the wiring schematics it shows that I should have an oil pressure switch and an oil pressure sender. the oil pressure sender is there but I cannot locate the oil pressure switch. when I pulled the motor both the blue and tan wire and the light blue wire were both going to the oil pressure sender I reconnected them the same way. the manual I have says in the notes next to the oil pressure switch "optional audio warning system circuit" I am guessing I do not have this but would that mean I don't have an oil pressure switch just an oil pressure sender and if so do both wires go to the oil pressure sender ?

 

[Bondo]

Ayuh,... Welcome Aboard,..... If yer motor has a mechanical fuel pump, the switch is optional,.....

If it's an electric fuel pump, the switch is a safety feature in the wirin' of the fuel pump,....

For yer gauge, Ground out the wire at the sender, 'n the gauge should Peg, Max,....

 

[bdubs217]

it has a mechanical fuel pump. Should both the tan/blue wire and the light blue wire be going to the sender or just the light blue?

 

[Bondo]

it has a mechanical fuel pump. Should both the tan/blue wire and the light blue wire be going to the sender or just the light blue?

Ayuh,... Ain't sure of the wire color,... Touch one to ground, if the gauge pegs, use that wire, 'n tape off the other,....

 

[bdubs217]

When I ground the blue wire the guage goes about half way. I taped off the other wire. Guessing half way means it's the gauge and not the oil sender.