No fuel at rail with KO/EO merc 350 mag mpi tow sport (02 centurion)

[jetskiD]

Hello, long time lurker, first time caller.
Working on our 02 centurion with the 350 mag mpi tow sport.
As of last few years and with it aging I have replaced cap rotor plugs injectors -the usual maintenance required.
Most recently I've had an issue with the boat cutting off as soon as I give it throttle.
I replaced the fuel pump and regulator on the rail with no better result.
So I hook my fuel pressure gage to valve on rail cross over and with the key on engine off, I have no fuel pressure, should i not have 40ish psi?? I unplugged the inline pump and turned the key on again. I hear what sounds like another pump priming! Is there a second pump?
Any help pointing me in the right direction would be appreciated.

Thanks, -Drew

 

[alldodge]

Welcome
What is your motor serial number?

You could have 1 or 2 pumps, just depends on what the motor configuration is and the serial number will verify.

Yes, you should get 43 psi at the rail

 

[jetskiD]

Welcome
What is your motor serial number?

You could have 1 or 2 pumps, just depends on what the motor configuration is and the serial number will verify.

Yes, you should get 43 psi at the rail

The serial is m312634

 

[alldodge]

Using SN 0m312634

You can have up to 2 pumps

The reason I say up to 2 pumps is because this was the change over period. If you do not have a pump Boost the fuel filter, you only have one pump which is below the port side under the motor mount.

Get a gas can, small or large doesn't matter. Disconnect the fuel line going into the fuel filter. Take a longer piece of fuel line and connect to filter input and place the other end into the gas can.

Cycle the key a few times to see if fuel pressure will build. Do bleed off air pressure in the gauge so fuel can flow thru

 

[jetskiD]

Using SN 0m312634

You can have up to 2 pumps

The reason I say up to 2 pumps is because this was the change over period. If you do not have a pump Boost the fuel filter, you only have one pump which is below the port side under the motor mount.

Get a gas can, small or large doesn't matter. Disconnect the fuel line going into the fuel filter. Take a longer piece of fuel line and connect to filter input and place the other end into the gas can.

Cycle the key a few times to see if fuel pressure will build. Do bleed off air pressure in the gauge so fuel can flow thru

I am able to build 10psi of fuel with pump above fuel water separator disconnected as you described. Leaning towards vapor lock or bad out of the box pump?

 

[alldodge]

It's not vapor lock
Might be you bought a low pressure pump instead of high pressure. What part number did you get?

 

[jetskiD]

Sir you are correct! I purchased the wrong pump initially. This is what I have being shipped currently EMP-1397-97004.

 

[jetskiD]

It's not vapor lock
Might be you bought a low pressure pump instead of high pressure. What part number did you get?

Correct pump is installed along with new copper cooler.
I am still not getting more than 10 psi at rail with my gauge.
Is there a specific bleeding procedure after having all those lines disconnected?
I have keyed on and off 50 times.
i have also tried pinching the return line from FPR mounted to cooler.
I did not replace the FPR only switched it to the new one. Did I screw up again? I thought the new cool fuel kit came with one but it didn't just the replacement screen.

Thanks for your time,
Drew

 

[jetskiD]

Correct pump is installed along with new copper cooler.
I am still not getting more than 10 psi at rail with my gauge.
Is there a specific bleeding procedure after having all those lines disconnected?
I have keyed on and off 50 times.
i have also tried pinching the return line from FPR mounted to cooler.
I did not replace the FPR only switched it to the new one. Did I screw up again? I thought the new cool fuel kit came with one but it didn't just the replacement screen.

Thanks for your time,
Drew

 

[alldodge]

No need to bleed to see pressure above 10 psi, the HP pump will push above 60 psi.

There are 2 things that control pressure, the pump and the regulator.

 

[jetskiD]

Ok

 

[jetskiD]

I have an OE fpr on the way. Thanks for the reply sir!

 

[jetskiD]

So I have now installed the new fpr. Key on engine off I can only make 24psi. I am sure I have the correct fuel pumps and the 43psi regulator. I have by passed the boats fuel tank completely and have a line from a gas can directly from a 2 gal can connected to first pump.
Any ideas?

 

[alldodge]

So I have now installed the new fpr. Key on engine off I can only make 24psi. I am sure I have the correct fuel pumps and the 43psi regulator. I have by passed the boats fuel tank completely and have a line from a gas can directly from a 2 gal can connected to first pump.
Any ideas?

Think of a garden hose, the water comes from the house (the pump). The spray nozzle (regulator) regulates the pressure based on how much nozzle is opened or closed

The high pressure fuel pump will produce more then 60 psi. Can bench test fuel pump on bench with gauge connected direct to pump

You had max 10 psi and now with a new Reg your getting 24 psi.
You did bleed some air off from fuel rail

Things that can keep pressure from pressure reaching 40 psi
1. HP Pump
2. Reg
3. leak

So KOEO and you get 24 psi and it holds pressure, this is either the wrong Reg or wrong pump

If pressure comes up to 24 psi and quickly drops off then there is a leak

43 Psi Reg should be 861126A1

 

[jetskiD]

So I have now installed the new fpr. Key on engine off I can only make 24psi. I am sure I have the correct fuel pumps and the 43psi regulator. I have by passed 5

Think of a garden hose, the water comes from the house (the pump). The spray nozzle (regulator) regulates the pressure based on how much nozzle is opened or closed

The high pressure fuel pump will produce more then 60 psi. Can bench test fuel pump on bench with gauge connected direct to pump

You had max 10 psi and now with a new Reg your getting 24 psi.
You did bleed some air off from fuel rail

Things that can keep pressure from pressure reaching 40 psi
1. HP Pump
2. Reg
3. leak

So KOEO and you get 24 psi and it holds pressure, this is either the wrong Reg or wrong pump

If pressure comes up to 24 psi and quickly drops off then there is a leak

43 Psi Reg should be 861126A1

807952A1 REGULATOR KIT (Mercury Marine) $169.49 Is what I just installed 🫠 dammit I feel dumb today! Guess I get to pull the cooler back out again!

 

[Scott06]

So I have now installed the new fpr. Key on engine off I can only make 24psi. I am sure I have the correct fuel pumps and the 43psi regulator. I have by passed 5

807952A1 REGULATOR KIT (Mercury Marine) $169.49 Is what I just installed 🫠 dammit I feel dumb today! Guess I get to pull the cooler back out again!

Do you order by engine serial number?

MerCruiser Motor Parts at MarineEngine.com

Buy from the largest online inventory of genuine MerCruiser stern drive parts including discount aftermarket parts. New and vintage parts available at MarineEngine.com.

www.marineengine.com

 

[jetskiD]

Do you order by engine serial number?

MerCruiser Motor Parts at MarineEngine.com

Buy from the largest online inventory of genuine MerCruiser stern drive parts including discount aftermarket parts. New and vintage parts available at MarineEngine.com.

www.marineengine.com

No I ordered what I thought was a 43 psi reg from this iboats

 

[jetskiD]

No I ordered what I thought was a 43 psi reg from this iboats

Didn't even know by serial was an option. I Learn new stuff everyday!

 

[Scott06]

Didn't even know by serial was an option. I Learn new stuff everyday!

Serial number will get you there marine engine and mercruiser parts.com among other have it via serial

 

[jetskiD]

Me again! Correct regulator installed, correct hpfp installed.
Can't get above 20 psi with many k.o cycles. Pressure holds steady when it does get there. Thoughts?
Bad fuel pump out of the box from quicksilver?

Pump/cooler kit installed
Fuel Cooler & Pump Kit | EMP 1397-97004

SKU: EMP-1397-97004

Regulator installed
861126A1