Adding a Fuel/Water separator, 2007 8.1 Mercs

[dpvandy01]

So my 38 with 8.1L Mercs has water in the fuel. It has the newly updated CoolFuel system (not paint) and no inline Fuel/Water separator. Boat is being hauled to get the H2O out of the tanks and I am thinking about adding inline Fuel/Water Separators to help down the road. Any thoughts or recommendations on brands?

 

[Lazy Daze]

Are you sure you don't have a filter? You should have a filter on the bottom/front/stbd side (of the engine, not as it sits in the boat) and that IS a fuel/water separating filter.

EDIT: On your engine, it will be a drop-in filter (there's a second one, disc-shaped, below it). Loosen the three bolts in the cap and use the handle to pull the cap off.

However, adding a spin-on/drainable filter at a more convenient location certainly wouldn't be a bad idea. I would add one for each tank. Racor is probably the biggest player in this realm. You'll find them under the Parker umbrella.

 

[Stee6043]

Seems impossible you don't have filters already???

I've got two mounted directly on the engines with another set on the bulkhead for a total of 4. All factory installed. Sometimes they are white, sometimes black.

 

[boatrboy]

Seems impossible you don't have filters already???

I've got two mounted directly on the engines with another set on the bulkhead for a total of 4. All factory installed. Sometimes they are white, sometimes black.

View attachment 133791

View attachment 133792

Like LD stated - he has the cool 3 which has two filters inside.

 

[WayneP]

I would stick with Mercury OEM brand filters. I installed an aftermarket well known brand and plastic parts melted and leaked. I now have two of them in line and they work really well. I have not had good luck with the ones that have a transparent bowl and bottom drain valve. Found that water was dripping off cockpit cover and into fuel cap that was missing a gasket/o ring. Replaced o ring and no more water in fuel. Fuel caps should have O ring installed at least on Sea Ray boats.

 

[mrsrobinson]

Why does the boat need to be hauled out to do get the H2O out of the tanks? I once accidentally put the fresh water hose in the fuel tanks on my sold 330DA. I realized it pretty quick and panicked. I ended up adding a solution that helps to get rid of the water, it was never an issue. Same thing with a boat I had under contract that had the 8.1s. Owner paid to have them pumped out at the dock.

 

[Lazy Daze]

I would stick with Mercury OEM brand filters. I installed an aftermarket well known brand and plastic parts melted and leaked. I now have two of them in line and they work really well. I have not had good luck with the ones that have a transparent bowl and bottom drain valve. Found that water was dripping off cockpit cover and into fuel cap that was missing a gasket/o ring. Replaced o ring and no more water in fuel. Fuel caps should have O ring installed at least on Sea Ray boats.

FYI, plastic bowls are specifically not allowed in this case. They should never be used with a sterndrive or inboard boat inside the engine bay.

Parker, as I noted, is an excellent brand.

 

[WayneP]

Fully agree re plastic. It was a name brand but still melted and leaked. Suspect counterfeit.... Re Parker, well know manuf of quality products. Sticking to Mercury and Parker for the two in line that I use. Have not had a problem since I added missing O ring to gas fill cap.

 

[paulswagelock]

Merc specifically says do not add a second external filter ahead of the cool fuel 3 module. It overworks the pump, heats up and dies an early death.
Your cool fuel module is a water separator.

 

[WayneP]

Good point. My engine, 383 MAG MPI has the first version fuel cooler, not the 3 which I have heard has some issues. Have you heard if Merc has anything to say about two separators? The first one is very free flowing, essentially a reservoir style separator.

 

[dpvandy01]

Good point. My engine, 383 MAG MPI has the first version fuel cooler, not the 3 which I have heard has some issues. Have you heard if Merc has anything to say about two separators? The first one is very free flowing, essentially a reservoir style separator.

My Cool Fuel 3's were replaced because of the know defect prior to my purchase. They also replaced all 16 injectors.