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Re: DIY Mercury EFI engine inline fuel filterS replacement
Posted: Sun Mar 27, 2016 1:01 pm
by Neo
Hi Catigale,
Just seen this post. I have this same motor and I'm sorry to say that you are getting to the high pressure filter the wrong way. The lower cowl unbolts quite easily and just pulls off the sides, giving very easy access to the filter. The hardest lower cowl bolt is the one at the front (inside) just under the fuel line socket. I undo it with a mini socket set, universal joint and long extension (and 10mm socket).
That filter protects the injectors and should really be replaced regularly.
All the best.
Neo
Re: DIY Mercury EFI engine inline fuel filterS replacement
Posted: Fri Apr 01, 2016 9:10 am
by Catigale
Thanks Neo - Ill have a look at that on my 50 (its a 2003) and see if thats easier.
Re: DIY Mercury EFI engine inline fuel filterS replacement
Posted: Fri Apr 01, 2016 11:34 am
by Neo
My one is a 2004 ....
I did the same as you when I first got my OB. But once that front bolt is undone the rest is too easy.

Re: DIY Mercury EFI engine inline fuel filterS replacement
Posted: Wed Jun 23, 2021 3:47 am
by Catigale
Bumping a 5 year old thread asa PSA for Mercury FAMILY EFI engines.
You have two fuel filters in these engines. I’ll see if I can document Neos cowl access method described above with pictures, too
Re: DIY Mercury EFI engine inline fuel filterS replacement
Posted: Wed Jun 23, 2021 2:24 pm
by Neo
Good luck with that.
May I just add that if your high pressure filter is black inside it may be that the two Nitrile (Rubber/Nbr) Grommets that are inside your VST are deteriorating.
See items 24 (Sleeve) and 25 (Grommet) here ...
https://www.boats.net/catalog/mercury/o ... -and-below
Decaying Nitrile accumulates at the bottom of the bowl.
Please note that once the VST is removed, opening it up MUST be done on a bench/clean environment (not bobbing up and down on the high sea's

).... And it's full of fuel so no smoking either
You may also need a new gasket (27) for reassembly.... Probably not an easy job if you're not familiar with taking carburettors apart?
All the best.
Neo
Re: DIY Mercury EFI engine inline fuel filterS replacement
Posted: Sun Jun 27, 2021 11:58 pm
by Neo
Hi Catigale,
Hope this information was useful?
All the best.
Neo