DIY Mercury EFI engine inline fuel filterS replacement

[Catigale]

Yes, as I learned today - you have TWO of them

Most of us know about the low pressure filter in the fuel bowl under the cowl....well....

I had a fuel delivery problem with my Mercury coming back from Cuttyhunk - I took off the fuel strainer, pumped some fuel into it, blew through the filter and I was on my way.

Today, in the driveway, no start. A shot of ether and it fired immediately - confirming fuel delivery problem.

With the service manual in hand, I discover there is a second fuel filter in the high pressure circuit, and I can see mine is black inside. There is no mention of this in the maintenance schedule, and it is buried in the engine (pictures to come) so wanted to alert

I have not serviced mine in 12 years of boating.,,I don't have tons of hours on this motor, I estimate about 300.

Tools

8mm socket
10 mm socket
Clippers for zip ties
zip ties, black 8 inch
New fuel filter part (order by serial number) Mercury 879885Q

Description: FUEL FILTER @2 (2 per pack) for 0 MERCURY 50 EFI (4 CYL.)(4-STROKE) 0T409000 THRU 1B344306

[RGF]

Just curious- ethanol or non-ethanol gas use? Thanks for the tip.

[Catigale]

Ethanol gas - Ive always just filled from local stations.

Once I get my new ones in, Ill cut this one open and see what is inside.

Ok, here we go.

First step - remove Cylinder 4 Coil - two 8mm bolts, spacers, then the coil slides off.

you can see how you will put it back on by tilting the coil so you can start the nut, then putting on the top nut, then tightening both. Its really hard to get the bottom nut started with the coil in the way. Note the carefully folded paper towel to catch any dropped nuts from falling into the Davy Jones Locker of the final drive



Ground point comes off, one 10mm bolt



Note bolt and washer order

[Catigale]

Now we move to the starboard side of the engine room and relieve the high pressure side of the fuel circuit



Extinguish all flammable materials, especially in CO and WA

Apply paper towel, push in red lock ring, pop off line - I had maybe 5 mL of fuel come out

[Catigale]

Back to port side

Disconnect relays and remove the lowest one for clearance - 10mm bolts



Disconnect manifold pressure sensor connector and dress the wiring harness to the front of the engine so you can access the inline filter

[Highlander]

Here,s the low pressure fuel filter on the left side on my Merc 75HP EFI u see the white filter near the end of the vid
http://vid844.photobucket.com/albums/ab ... b8e73b.mp4

Here u can see the white high pressure fuel filter on the front of the eng , mine r reasonably accessible
http://vid844.photobucket.com/albums/ab ... afd3e6.mp4


J
Mine r a lot easier to replace LOL

[Catigale]

this is your first few of the beast



Clip the zip ties on the harness (one or two black ones) then slide the sheath back to reveal....



the beast......

Its comes off just like the other high pressure line, push in the red clip and pop the filter off. About 10-15 mL of fuel will drain from the line.

[Catigale]

I ordered a two-pack of filters from mercury parts direct for 21 USD

Mfg Product Number: 879885QDescription: FUEL FILTER @2 (2 per pack) for 0 MERCURY 50 EFI (4 CYL.)(4-STROKE) 0T409000 THRU 1B344306Order Quantity: 1Unit Price: $20.66Total Cost: $20.66Mfg

[Catigale]

Rant mode on.

I confess Im a little tweaked by this. I had no knowledge of this filter, and it does not appear in the maintenance schedule in my service manual. Maybe its in my user manual, but I confess I out that aside as I thought the maintenance and service manual would be more comprehensive.

I like to think I take care of my stuff, and yet here I am at sea on a 13 year old fuel filter. Thats sits well with me not.

[RGF]

WOW! Thanks for the step-by-step, Cat!

[Russ]

Rant mode on.

I confess Im a little tweaked by this. I had no knowledge of this filter, and it does not appear in the maintenance schedule in my service manual. Maybe its in my user manual, but I confess I out that aside as I thought the maintenance and service manual would be more comprehensive.

I like to think I take care of my stuff, and yet here I am at sea on a 13 year old fuel filter. Thats sits well with me not.

Makes you wonder if a Merc mechanic would have known as well. Would this baby have been missed if you paid someone to do it?

I have also maintained my own mechanicals as well. I remember my first car, a big old 455ci V8 giving it a tune up and after struggling so hard to remove the last spark plug discovering it was totally encrusted in gook. Apparently every mechanic before found that plug equally difficult to retrieve and decided to just leave it for the next tune up mechanic.

This however is a good lesson in doing your own service. You know it's DONE and done right. Well as long as you have the information (manual) to tell you what needs to be done. I have seen boats "winterized" and engines "serviced" to learn NOTHING was done except invoice the owner.
Warning for those who let dealers maintain their motors, after a service, check your oil to see that it's new. Check the motor for signs of work done. Not that I don't trust mechanics (smile) but I would even take nail polish and mark bolts that must be removed for water pump replacement.



Nice write up Steph. Hopefully some others will now check their filters and get 'em changed out.

--Russ

[Catigale]

If you paid someone to maintain your motor, look at your wiring harness zip ties. If they haven't been moved, they missed it. Of course, this isn't on the maintenance schedule either

[kurz]

Thank you for the photos of the filter.

Does anybody knows why it is in a rubber condom?

It makes handling quite fuzzling...

[Catigale]

There are a lot of wire looms and the engine block is there too. That will be quite warm during running, so the rubber sheath would keep heat from the fuel filter too.

[Catigale]

And the verdict is in, this filter was really, really dirty....