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525EFI Electric Fuel Pump Upgrade?

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Old 07-28-2007 | 03:35 PM
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Question 525EFI Electric Fuel Pump Upgrade?

Has anyone blocked off the mechanical fuel pump and replaced it with an electric inline fuel pump?

Which pump is recommended to do the job?

Thanks.
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Old 07-30-2007 | 09:45 AM
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Why´d you wanna do that? I asked once why Merc racing runs the mechanical pump and I believe it was a reliability issue in racing conditions. The only merchanical pumps that give trouble are on old motors that stood for a while.
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Old 07-30-2007 | 10:51 AM
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Because of this problem:

http://www.offshoreonly.com/forums/s...d.php?t=164490
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Old 07-30-2007 | 11:21 AM
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I'll keep my mechanical pump thank you.

It eliminates vapor lock when it's hot, and/or high.

Does require seasonal pm though.

Pesky Varmint
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Old 07-31-2007 | 04:41 PM
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Wow!
Interesting thread!
Like many others including yourself, I hadn´t been aware of this problem on a 525. My friend (who has a 500Efi) told me to diconnect the breather from the pump to the intake.
I´ve got 120 hours on my 2006 motor. I´ll check it!
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Old 08-01-2007 | 09:21 AM
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I looked at a 90 Formula last weekend that look like it had newer EFIs in it. It as still running the old Gen IV water pump steup, without the fuel pump, so someone had added a couple electric holley fuel pumps to get fuel to the EFI pump.
BTW, the problem with it was a failed EFI pump and injector problems. So I'm thinking the electric pump swap may not be the answer.
Gary
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Old 08-01-2007 | 03:39 PM
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Originally Posted by rdoactive
I looked at a 90 Formula last weekend that look like it had newer EFIs in it. It as still running the old Gen IV water pump steup, without the fuel pump, so someone had added a couple electric holley fuel pumps to get fuel to the EFI pump.
BTW, the problem with it was a failed EFI pump and injector problems. So I'm thinking the electric pump swap may not be the answer.
Gary
Electric pumps in general need ample supply, so in turn the low pressure pump would need to be at the tank.

The more I research, it seems an electric pump will solve the contamination problem, but create a fuel delivery problem.
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Old 08-02-2007 | 08:14 AM
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I've used Mallory electric pumps on Gen V 525SCs with no problems. A lot of electrics are mounted too high or too far from the tank to work well. I dont see why a well put together setup with a 7 psi electric feeding the EFI pump would not work. Just has to be done right.
BTW the electric on the Fountain was 3' from the fuel tank and at the level of the top of the tank. Not good.
Gary
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Old 08-02-2007 | 12:25 PM
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Thanks for the information Gary. That is what I am hoping to accomplish.

Originally I was planning on mounting the low pressure electric pump low in the bilge area where the fuel cut off valve is coming from the tank.

Did you use the fuel pump wire from the ECM to trigger the relay for the low pressure pump?

Sal
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Old 08-02-2007 | 12:36 PM
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I set mine up on carbed motors and used a hobbs switch on the oil cooler port (for trucks) on my gen V motors. But there's no reason I can see to make it more complicated for an EFI motor. Keyed ignition and starter bypass to open and close terminals of hobbs switch, respectively. The common to a relay. Relay supplies current to the pump.
Gary
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