Electric fuel pump question

Yareck

Yareck

Member
Jan 18, 2014
82
Fort Lauderdale
Boat Info
1996 27' SeaRay Sundancer
Engines
7.4L MPI Mercruiser w/Bravo III Drive
I have mercruiser 1996 7.4 MPI. My electric fuel pump is not performing right. There's not enough pressure and boat won't go above 2000 RPMs. This pump is inside of the vapor separating tank.
New pump costs $800 which is crazy and what I was told there's no aftermarket pumps for this engine.
Can those pumps be fixed?
If so do you know where can I send it?
Maybe there's a pump that can substitute this one? I see there's many similar looking pumps on line.
 
I would look into using any kind of high pressure pump. Look into the 6.2 mpi fuel system. It uses a boost pump and then a high pressure pump
 
Bt Doctur said:
I would look into using any kind of high pressure pump. Look into the 6.2 mpi fuel system. It uses a boost pump and then a high pressure pump
Click to expand...

You think any pump that will fit in VsT tank will do? I can buy one for $100
 
Most mpi`s like to have 40-42 psi at the rail
eliminate the tank and plumb in a new system. With the fuel injection systems out there you have to keep the fuel cool to prevent a vaporlock, The manufactures come with all these fancy way to cool the fuel ,expensive ones when a simple fuel cooler can be made using the transmission coolers for inboards.
Lowering the fuel temp before it gets to the engine`s fuel pump . A inboard trans uses threaded fitting so your half way there. If the current fuel lines can handel 45 psi they can be plumbed into a trans cooler
 
Last edited:
Engine number is 0F602266. I can't find pump number
Bt Doctur said:
https://www.ebay.com/i/152233867153?chn=ps&dispItem=1
Click to expand...
Bt Doctur said:
Most mpi`s like to have 40-42 psi at the rail
eliminate the tank and plumb in a new system. With the fuel injection systems out there you have to keep the fuel cool to prevent a vaporlock, The manufactures come with all these fancy way to cool the fuel ,expensive ones when a simple fuel cooler can be made using the transmission coolers for inboards.
Lowering the fuel temp before it gets to the engine`s fuel pump . A inboard trans uses threaded fitting so your half way there. If the current fuel lines can handel 45 psi they can be plumbed into a trans cooler
Click to expand...

Mine shows 35-38 PSI. I'll just buy new pump since it's only $25. Comparing to $700-$800 I was quoted.
 
Bt Doctur said:
Most mpi`s like to have 40-42 psi at the rail
eliminate the tank and plumb in a new system. With the fuel injection systems out there you have to keep the fuel cool to prevent a vaporlock, The manufactures come with all these fancy way to cool the fuel ,expensive ones when a simple fuel cooler can be made using the transmission coolers for inboards.
Lowering the fuel temp before it gets to the engine`s fuel pump . A inboard trans uses threaded fitting so your half way there. If the current fuel lines can handel 45 psi they can be plumbed into a trans cooler
Click to expand...

Do you know any websites where I can see how this system should be installed?
You got me interested
 
Bt Doctur said:
5A-6 in here http://www.boatfix.com/merc/Techbk/97/97hga5.pdf

http://www.boats.net/parts/search/Merc/Mercruiser/1998/4S4225JN1/COOL FUEL SYSTEM/parts.ht
Click to expand...

Thank you for the info.
First question: where is the return from the fuel rail going ? I don't see any?
Second question : in case of gas vaporizing in lines where is it going once I would like to start the engine. I was experiencing pretty bad vapor lock two years ago due to vst malfunctioning so I know the pain
 
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