3 wire vs 4 wire fuel pump

[Plumbroke]

The four wire fuel pump in my 120 hp Evinrude is bad. I have a 3 wire fuel pump in a blown 110 hp Evinrude that I know was working 3 weeks ago before it died. anyway of using the 3 wire in the 120?

 

[seahorse5]

Re: 3 wire vs 4 wire fuel pump

The pumps are different internally plus you do not want to use a 3 wire pump as the alarm system sometimes did not work correctly if there was a regulator problem.

The factory replacement pump kit is now universal for all J-E engines and comes with various fittings for different model engines.

 

[boobie]

Re: 3 wire vs 4 wire fuel pump

You can use the 3 wire vro. The only problem you might have is false no oil signals. The 4th wire was added to help eliminate those signals and it was the purple wire. You may have to do some wire changing.

 

[Plumbroke]

Re: 3 wire vs 4 wire fuel pump

So the other three are color coded correctly and just don't connect the purple one?

 

[boobie]

Re: 3 wire vs 4 wire fuel pump

Yes........

 

[Plumbroke]

Re: 3 wire vs 4 wire fuel pump

Thanks!

 

[seahorse5]

Re: 3 wire vs 4 wire fuel pump

It's been a lot of years since they changed from 3 wire to 4 wire alarm circuits. The purple wire powers the electronics for the NO OIL alarm and if it is left off, then I believe that your alarm will not work correctly.

The older 3 wire alarm used a rectifier circuit in the electronics to tap power off of the tachometer signal. That is why the system was changed to 4 wire because of the problems getting an accurate alarm when needed as the rectifier circuitry was subject to malfunctioning from voltage spikes from loose battery cables, etc.

 

[boobie]

Re: 3 wire vs 4 wire fuel pump

You are entirely correct Seahorse but it sounds like he doesn't want to buy a new vro. But I warned him in post # 3 about this.

 

[Plumbroke]

Re: 3 wire vs 4 wire fuel pump

I only have $1000 in the motor, retired on fixed income, so I will probably risk it and watch oil consumption closely. I really appreciate both inputs.
mike