1999 Rinker 4.3L fuel pump issues

[Sxtysix]

Boat is a 1999 Rinker 21' 4.3L 2bbl Carb....Fuel pump isn't priming but bench tests good, I have 12v to the pump while cranking but once engine starts 0v to the pump... thinking it has to be one of the safeties not allowing voltage to the fuel pump replaced the oil sender and pressure switch a few weeks ago and engine has ran great until today. Unsure how to test and trouble shoot from here

 

[Bt Doctur]

pressure switch should have 12v on one side ,other side goes to the pump .pull the plug and jump across the pins, pump should run.Yes= replace pressure switch. I have found that when the fuel pump tries to draw more current than the switch can handle is goes bad. I wire in a cube relay to operate the fuel pump and use the pressure switch to operate the relay.

 

[Sxtysix]

pressure switch should have 12v on one side ,other side goes to the pump .pull the plug and jump across the pins, pump should run.Yes= replace pressure switch. I have found that when the fuel pump tries to draw more current than the switch can handle is goes bad. I wire in a cube relay to operate the fuel pump and use the pressure switch to operate the relay.

Thanks for the reply....Is that 12v at the oil pressure switch with the key on or while cranking?

 

[Rick Stephens]

When the key is on, there is power at one side of the pressure switch. Other side of oil pressure switch gets power when oil pressure comes up and is the primary power source for the pump.

The fuel pump also gets power from the small outside lug on the starter solenoid. This supplies power to the fuel pump to prime the carburetor while the starter is cranking the engine over. Note, this will also show up on the pressure switch as power at both terminals even though the pressure switch is not 'ON' yet from oil pressure building up. The side of the pressure switch towards the pump is also teed off to the primer power from the starter. Same circuit.

 

[Sxtysix]

Thanks guys I appreciate the info

 

[Sxtysix]

With key on I have power to the solid purple wire on the oil pressure switch.... cranking I have power to the other side of the oil pressure switch which is the purple with a white strip wire which is the hot wire for the fuel pump and also runs off the starter solenoid... key on there is no power to the fuel pump, pump only gets 12v while cranking and if I fill the bowls in the carb to where it does start the fuel pump no longer has 12v

 

[Rick Stephens]

Bad oil pressure switch.

To keep that from happening add a relay.

 

[Sxtysix]

Thanks Rick... just bought one 3 weeks ago looks like I am going to go exchange it

 

[Sxtysix]

Bad oil pressure switch.

To keep that from happening add a relay.

Swapped out the pressure switch and that fixed it... thanks everyone for the help and input

 

[Bt Doctur]

Now install the cube relay. If the fuel pump is drawing more current than the switch can pass it burns out
Almost all places have no warranty of electrical items

 

[Rick Stephens]

Or carry a bunch of spare oil pressure switches