Whaler Central - Boston Whaler Boat Information and Photos

Posted by Manasota on 06/22/20 - 9:25 PM

Planning on install of a fuel/water separator on my 2001 Ventura 21. Engine is a Mercury 225 HP EFI 2 stroke. Any recommendations?

I am also questioning why this motor needs an additional filter between the tank and the motor. I thought the Merc EFI had a separator built in under the "hood"??? Also, wondering what happens to the water that the filter separates from the fuel if filter has no drain???? The basic Mercury filter has no drain and am told by the Mercury dealer in my area that the filter is good for about 100 hours. Questions, questions, questions need answers, answers, answers!

Edited by Manasota on 06/24/20 - 1:39 PM

Posted by acassidy on 06/25/20 - 9:25 PM

Boats are very different than cars in that they set up for long periods of time unlike a car which is driven often and always gets fresh fuel.

Fuel filter water separators do two things, trash and water removal. Most trash will will things like fuel varnish and corrosion from inside the tank. The Mercury filter does also filter but think about how big your tanks is compared to the Mercury filter. Fuel is lighter that water so any water will be in the bottom of the fuel separated completely from it. This means that any water in the tank will be first thing to be sucked by the pick up and the filter will hold the water in the base of the filter and not go into the outboard. That filter on the outboard is more of a last chance of cleaning filter before being used.
Good rules of thumb for installation.

1. Place the filter close to the outboard as close as you can in the transom area. Filter needs to be placed with the base at the top and level.
2. Place the filter at a level that is higher than the level of fuel in the tank. If lower than the tank you will siphon fuel from the tank while trying to change the filter and in an emergency leak the tank will be siphoned into the boat.
3 Put primer bulb before the filter if you can.
4. Use under deck fuel hose that for that are rated by Coast Guard. This is not the hose you can buy at Academy.
5. Use stainless hose clamps

I am keeping this short but really a book could be written on boat filters. Bottom line is I would not own a boat with out one. On my boat I have a Racor filter with site bowl on the bottom which can be drained without filter removal. Site bowls cannot be used below deck in compartments but they also make metal bowls which can. If there were, God forbid, a fire below deck it will melt the bowl and then you now have a fuel fire.

Kind of surprised your boat does not already have one. Moeller also makes great filters. Any filter is better than non.
Archie

Posted by Finnegan on 06/25/20 - 10:36 PM

I have a few opinions contrary to the above post. I have an Outrage 25 with twin Mercury EFI V-6 engines.

The engines do have their own water separating filter, a smaller sized version of the standard filter. It is alarmed to indicate when it accumulates water. I have heard that with a filter like this on the engine, a main tank Water Sep filter may not be necessary, and may cause too much fuel flow restriction, which is probably why your boat does not have one. On my boat, however, I do use the main tank separators also, one for each engine. I have never found any water in any of the filters over the last 31 years! I change the boat filters every three years, and have NEVER had to change out an engine mounted filter, as they are a second line of defense in my situation.

I doubt that a boat mounted filter will restrict fuel flow, so if you want a main tank water separating filter, go ahead and try it. I see you are in FL, so you most likely do not have the cold condensation conditions that half empty tanks can suffer up North. Your main risk of getting water in the tank is from your fuel source tanks, not very likely.

I would use a simple Mercury/Quicksilver branded filter and head. They are small and compact, and have become the most commonly used filter, readily available, and also in the aftermarket.

I would never mount a filter in the boat splashwell, where they are subject to salt corrosion.
Instead, put them in a dry location, out of sight if possible, readily accessible from inside the boat. Under a gunwale is a good choice.

Mercury requires the primer bulb be AFTER the filter, so engine priming is efficient. Otherwise you are forced to pump fuel through the filter in order to prime the engine.