Fuel Pump Question

Quarterwave

Petty Officer 2nd Class
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Sep 16, 2013
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118
Hi everyone,

I'm in the process of converting a 5.7 SBC for a marine application. The long block that I purchased did not have a fuel pump, so I ordered a new one which looks like photo #1.

For comparison, the fuel pump on the old, 5.0 Mercruiser is in photo #2. You'll notice that I added two red arrows showing where the housing bolts to the block.

The issue that I'm facing is that style mechanical fuel pump doesn't seem to fit on the block that I purchased (1986-cast, non-Vortec head). Please see photo #3 for where the fuel pump is supposed to attach to the block. As you can see, there is only 1 bolt hole.

What am I missing here? Do I need to install an electric pump? If so, can I install it inline? As there is no room in the tank for sending unit and also a pump.

Any input is much appreciated.
 

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Bt Doctur

Supreme Mariner
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Aug 29, 2004
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19,093
The late model motor needs the electric fuel pump,there is no mechanical pump ,nor is there a hole for the fuel pump rod to operate the pump.
And NO, you cant drill one

I have a post about installing a electric pump neatly
 

Bt Doctur

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Aug 29, 2004
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you will need 2 holes to mount a pump Done correctly it should not be a problem .You will know where when you get the pump
 

G_Hipster

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Sep 24, 2016
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There is a fixture to drill the pump pushrod hole available. It's a pricey tool. A better machine shop might have this, but it really requires the block to be disassembled for cleaning purposes after the operation is done. I'd go the electric pump route.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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47,306
carter electric fuel pump for marine use is about $80 make a bracket to install to your motor, or if you are taking the motor apart, have the block machined.
 

Quarterwave

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Sep 16, 2013
Messages
118
Thanks everyone. As I just assembled the motor from the short block, I don't really want to pull it all apart to have a hole bored into the block.

BT Doctur - thank you for the link, but I have some questions as I can't see the details in the images that are posted in the link.

1) What gauge steel for the bracket?
2) What torque setting for the bolt that bolts that bracket to the block?
3) What holes were drilled into the bracket?
4) How do I get power to it? I'm learning electrics on this engine and are getting to the installation of the distributor, plugs, plug wires, coil and whatever else is needed in the coming weeks. Any help would be really appreciated.

Scott - thanks for the tip on the Carter pump. I'll return the existing one and look for that brand.
 

Bt Doctur

Supreme Mariner
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Aug 29, 2004
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19,093
1 its about a 1/8 inch thick
2 3 fingers with a 3/8ths ratchet
3 The drilled holes matched to the lower 2 holes for the fuel pump blockoff plate that you dont have
4 you use a oil pressure switch 2-6 psi, Standard automotive part. A fuel pump relay from a Chevy Blazer.(30 amp rating)
You get power from the slave solenoid relay mounted on the front of the motor.The pressure switch operates the fuel pump relay ,and the relay powers the fuel pump.Sometimes a fuel pump goes bad and draws more current than the oem pressure switch can supply and burns out. Most pumps will draw up to 5-10 amps working properly .
can do a diagram if needed
 

Bt Doctur

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I know ,I should have taken the pics before I painted everything black
 

Quarterwave

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Sep 16, 2013
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Thanks BT. When I start working on it this weekend, I'll be sure to reach out if I can't figure it out! (very likely!).
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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the S-10 blaser relay is a standard VF4 relay available nearly anywhere parts are sold
 

Quarterwave

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Sep 16, 2013
Messages
118
Hi Scott, yes a diagram would be really helpful if you have time. I having a difficult time working out how to get power to the relay and what the relay sits in? Every relay that I've seen in cars sits in a dedicated fuse box with a bunch of other relays.

From what I can tell for my boat, there really is no fuse box anywhere near the engine bay.

BTW - I'm looking at a Carter P4389, 4-6 PSI marine-grade fuel pump. With that work for the 5.7 Mercruiser application?
 

Bt Doctur

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Are you using the standard fuel/water sep bracket with 50A cb ans slave solenoid?
 

Bt Doctur

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comes with a mounting bracket.
pco-5593c_ml.jpg
...................
 

Bt Doctur

Supreme Mariner
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Messages
19,093
BTW - I'm looking at a Carter P4389, 4-6 PSI marine-grade fuel pump. With that work for the 5.7 Mercruiser application?

Will be perfect
 

Quarterwave

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Sep 16, 2013
Messages
118
Yes - using the standard water/fuel separator bracket - which actually leads me to another question! I was trying to put that bracket on the engine earlier tonight and just cannot find where it attaches to the block. The bolt holes on either end are not lining up with anything on the block. Does anyone have a photo of how the bracket mounts?

I thought I took one with my phone but can't seem to find it and Google image search is not really showing me anything...
 
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