Oil, pressure safety switch

Erico624

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Hello going crazy trying to find a three pin oil pressure safety switch. Can somebody please help me or direct me where to buy a new one?
 

Scott Danforth

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Napa has 3 pin oil switches in stock

I have links to the catalog in the electrical stickies
 

nola mike

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Afaik the ps-64 is the only other one at least that I could find. I've had both fail multiple times unfortunately.
 

Bt Doctur

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the reason most fail is because the electric fuel pump starts drawing more current. this burns out the contacts in these and also the mercruiser ones. the trick is to run the fuel pump thru a cube relay and just use the pressure switch as a contact point for the low current internal cube relay
 

Scott Danforth

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Use the switch to power a relay

Use the relay to power a fuel pump
 

nola mike

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the reason most fail is because the electric fuel pump starts drawing more current. this burns out the contacts in these and also the mercruiser ones. the trick is to run the fuel pump thru a cube relay and just use the pressure switch as a contact point for the low current internal cube relay
Mines wired to a relay. I think it just isn't great around salt. Or I'm unlucky.
 

Erico624

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Use the switch to power a relay

Use the relay to power a fuel pump
Yup this is how it’s hooked up. I have power from 50 amp breaker to relay for 12v they wire from ignition switch to oil pressure switch. Then pin from switch to yellow wire to relay. Just not getting 12 volts from the yellow wire
 

Scott Danforth

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Pin 30 to power
Pin 85 or 86 to the oil pressure switch NO contact
Ground to oil pressure switch C contact
Pin 86 or 85 to the ignition switch
Pin 87 to the fuel pump
 

Erico624

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Pin 30 to power
Pin 85 or 86 to the oil pressure switch NO contact
Ground to oil pressure switch C contact
Pin 86 or 85 to the ignition switch
Pin 87 to the fuel pump
auto parts Standard , oil pressire/fuel pressure switch
PS-64 or Carter A68301
Never had good luck with Standard parts. When I was tech we use to have a lot of returns of faulty sensors.
 

sdowney717

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Lots of pressure switches here
One has slide on terminals, one has screw on. And you should use a cube relay.



But you can use a 2 wire NO switch, and run a wire from starter to the fuel pump and get pump running as engine cranks without using a relay. Run it off the starter solenoid 'R' terminal, it only gets power when engine cranks over by starter. Years ago, 'R' was used to give full voltage to the ignition coil when cranking, bypassing the coil resistor.

 

Erico624

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Lots of pressure switches here
One has slide on terminals, one has screw on. And you should use a cube relay.



But you can use a 2 wire NO switch, and run a wire from starter to the fuel pump and get pump running as engine cranks without using a relay. Run it off the starter solenoid 'R' terminal, it only gets power when engine cranks over by starter. Years ago, 'R' was used to give full voltage to the ignition coil when cranking, bypassing the coil resistor.

Yeah I use a relay already
 

Scott06

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if you find one in the brand you want but its 1/4" you could use an adapter like this

 

Erico624

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if you find one in the brand you want but its 1/4" you could use an adapter like this

I have the adapter on there already. Just want to find one that will last and not die after 30 days like the Carter one.
 

Scott06

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I have the adapter on there already. Just want to find one that will last and not die after 30 days like the Carter one.
these guys may have one -


i got a sending unit for my 65 GTO that had a different ohm range so I could make my factory gauge read 0-80 psi vs the factory 0-60.

Had a good collection of senders/switches. They had some Hella units which are good OEM quality. Didn't spend a lot of time looking, but In the end I think you only need a 2 wire switch not a 3 wire.

if the switches just have one wire making connection to ground you could trigger the negative side of the relay coil.
 
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sdowney717

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I have the adapter on there already. Just want to find one that will last and not die after 30 days like the Carter one.
You can go to a typical reliable Mercruiser oil pressure switch with 2 terminals, 1/8" NPT.
It comes with the pigtail connector. It closes when oil pressure hits 4 psi.
And to run the pump when cranking engine for starting, use the starter 'R' terminal
Completely abandon what you have with that 3 terminal unreliable switch .

Part number is

Mercury Fuel Pump Oil Pressure Switch 87-864252A01​



The part number is available as cheap as about $10 on ebay and Amazon.
Example
 
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