Mercury 40 HP Fuel System Rebuild | Mercury 40 HP Fuel Pump Replacement |

Mercury 40 HP Fuel System Rebuild | Mercury 40 HP Fuel Pump Replacement |

See the parts, including a Mercury 40 HP fuel pump kit and more here:

See how to rebuild the fuel system on your Mercury 40 HP EFI outboard in this video from This motor hasn’t run in a while, so we knew going in that there were going to be issues. What we didn’t was that the motor would be missing a fuel pump! We’ll get that first fuel pump replaced, and then we’ll dig deeper into the fuel system.

John will show you how to remove the VST and open it to inspect the components. We’ll replace the VST pump and the float needle, and then get the tank closed back up and reinstalled.

See a Mercury 40 HP EFI fuel pump diagram here:

See the lower cowling diagram here:

See the VST tank diagram here:

See the Mercury 40 HP fuel line diagram along with the Mercury 40 HP fuel filter here:

Read how to do this job step by step:

Installing new fuel pump – 1:50
Removing VST tank – 3:50
Disassembling VST tank – 6:50
Removing VST fuel pump – 9:25
Replacing VST pump – 10:20
Installing VST tank – 12:17

Find Mercury 40 HP outboard parts here:

Talk to us:

In the video we’re working with a 2003 Mercury 40HP 4-stroke outboard motor, but you may have similar steps for your Mercury outboard. If you’re not sure whether these steps apply to your motor, leave a comment and we’ll get back to you.


Mercury 40 HP output seal replacement:

Mercury 40 HP water pump repair:



Richard Mehalick says:

What temperature should the Zip ties be rated for?

Luiz Araujo says:

Hello, how are you? I'm from Brazil, I wanted to do some research! I have one of these, I would need that VST tank, how much does a new one cost?

Fernando Felan says:

I have a 2014 Mercury efi 60hp my vst is leaking fuel out of the bottom hose. What would cause this?

Roald Stroomberg says:

Great video, helped alot and the website is very to use. But i can't have them shipped over to the netherlands for some reason ?

Adrian Ol says:

How you test hight pressure pump? Can you connect it to 12volts to see if works?

Chris says:

Great video, very professional. I plan on T/S one of these this weekend for poor low and high idle. This helped me know what to expect with the fuel system.

wally tavera says:

I have a 40 horse Merc and fuel is coming out of the bottom carburetor at the plunger is there a rubber gasket that's in there that might be pushing fuel back out when it is pressurized

Gary Appleby says:

Need parts list

B B says:

I need the whole vst pump…
How much they run ?

kenneth de wolff says:

Learn lot again, thx

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