fuel water separator filters

[captn tj]

Outside of the Micron rating (my manual specifies 10 microns for my 225 4 stroke) is there any difference in the size of the filter or brand? I saw a large Sierra (model 18-7866) and a smaller version same brand. Also a large Racor with a plastic bowl on the bottom (model 320-rac-01) which specifies for outboard engines only. I was under the impression that you can't use plastic bowls with gas.

While I'm relatively new to outboards, I've been around boasts with diesel engines for the past 25 years and am surprised to see few if any separators with bowls so you can see any water.

[boscoe99]

Outside of the Micron rating (my manual specifies 10 microns for my 225 4 stroke) is there any difference in the size of the filter or brand? I saw a large Sierra (model 18-7866) and a smaller version same brand. Also a large Racor with a plastic bowl on the bottom (model 320-rac-01) which specifies for outboard engines only. I was under the impression that you can't use plastic bowls with gas.

While I'm relatively new to outboards, I've been around boasts with diesel engines for the past 25 years and am surprised to see few if any separators with bowls so you can see any water.

The size of the filter determines the amount of fuel that can flow through at a given rate while not having more than XYZ pressure drop. It can also capture more debris for a longer period of time before it needs to be replaced.

As you note, there are filters with no bowls and there are filters with bowls. Metal and plastic bowls. If a plastic bowl is used it has to meet a fire test requirement if the bowl is used on an inboard powered boat. As far as I know there are no plastic bowls that meet the fire test. So, the plastic bowls are OK to use with an outboard motor (above or below deck) but are not approved for use with an inboard or I/O powered boat.

The Racor with the plastic bowl seems to have the most usage. Before each trip you can inspect the bowl for the presence of any water. If any then it can be drained off using the tap at the bottom of the bowl.

Now what some also do is to install a vacuum gauge at the outlet of the filter. This way you can see if and when the filter gets clogged to the point that it needs to be changed. Without a vacuum gauge there is no real way to know. Maybe the motor running poorly due to an fuel flow restriction might be an indication but by then it is later than it needs to be.


Here is a Yamaha dealer that sells Racor and Yamaha branded filters

Search

Yamaha offers filters with no bowls, filters with metal bowls, filters with plastic bowls and filters with bowls that have a sensor in the bowl to indicate the presence of water.

2015_Yamaha_MRP

[TownsendsFJR1300]

I keep a new spare fuel filter (W/O the plastic bottom) on- board just in case something breaks the plastic one while out on the water.

[fairdeal]

I would be very interested in hearing from anyone using E-10 - and a "clear bowl" - who has ever seen any water in it.

With "real gasoline" they certainly effectively "separate" droplets of water

But my impression is that, with E-10, if you find water in the filter bowl,
you have just found out that you need to drain your entire tank of its contents of "phase separated" fuel

[boscoe99]

My understanding is that phase separation only comes about when X percent of water gets into E10 ethanol (90% gasoline and 10% alchol). Below X percent the water does not co-mingle with the alcohol such that the E10 ethanol remains E10 ethanol and the water remains water. Above X percent the water can mingle with the alcohol and then the alcohol/water mix drops to the bottom of the tank.

In the case of my Racor I put ethanol in the boat tank and from time to time would have drops of water in the Racor bowl. Simply drained it out. Never had a problem with ethanol.

Do a test. Get a vial. Add some ethanol to it. Add a drop of water to it. See if the water goes to the bottom of the vial. Shake the hell out of the vial and see what happens. Now add some more water to the vial. Maybe a teaspoon or so. Shake the hell out of the vial and see what happens. I am thinking the results will different.

[robert graham]

It's a lot about the size of your boat/motor and fuel tank. A 40 or 60 gallon under deck gas tank has the potential for more water/fuel issues since there's so much more fuel. My boat has a portable 12 gallon tank which can be inspected, removed, drained and flushed out if necessary, so I use a Walmart/Attwood fuel/water separator($28) and it's all I need and I can easily unscrew it and dump it. The clear drain-able bowl types are really nice but more expensive and not coast guard approved for enclosed/below deck installations. The Yamaha and Racor folks may help recommend their ideal filter for your particular application. That said, I believe that the fuel/water separator type cartridge filters are among the very best preventive maintenance items that you might add to your boat/motor.

[boscoe99]

It's a lot about the size of your boat/motor and fuel tank. A 40 or 60 gallon under deck gas tank has the potential for more water/fuel issues since there's so much more fuel. My boat has a portable 12 gallon tank which can be inspected, removed, drained and flushed out if necessary, so I use a Walmart/Attwood fuel/water separator($28) and it's all I need and I can easily unscrew it and dump it. The clear drain-able bowl types are really nice but more expensive and not coast guard approved for enclosed/below deck installations if the boat is powered by an inboard or an inboard/outboard motor. The Yamaha and Racor folks may help recommend their ideal filter for your particular application. That said, I believe that the fuel/water separator type cartridge filters are among the very best preventive maintenance items that you might add to your boat/motor.

Use of a drainable fuel filter with a plastic bowl can be used in any part of the boat as long as it is powered by an outboard motor.

[robert graham]

Use of a drainable fuel filter with a plastic bowl can be used in any part of the boat as long as it is powered by an outboard motor.

That clarifies it.....

[rodbolt17]

folks it all goes back to simple 8th grade organic chemistry.
its not difficult.
Ethanol is a simple organic solvent with a rather large molecular structure.
its highly corrosive and hydroscopic.
means it corrodes stuff and attracts moisture(water) from the atmosphere(air).

most marine gas fuel systems prior to January of 2010 vented the tank directly to the atmosphere.

means any E in the G starts absorbing water from the tank vent.

once the E in the G starts this it cannot be filtered with a standard water separator.
one gallon of the E can hold in its molecular structure about 1 quart of water.

at 10% E that means every ten gallons of E10 can hold about 1 qt of water in suspension that cannot be filtered.
however now we toss in air/fuel temperature.
raise the temp and the water starts falling out,fuel bowls and VST tanks.

its called super saturation for those that failed 8th grade science.
its also how we made rock candy.

E fuels, also known as the marine technician stimulous program, are the dumbest thing ever shoved down the US taxpayers throat.

however its what we have and are stuck with so do a bit of 8 grade organic chemistry and turn your fuel regularly.

[boscoe99]

I think that you meant to say that when the temperature is lowered the water that is/was suspended in the gasoline mix will precipitate out of the gasoline and drop to the bottom of the tank.

Gasoline will hold more water in suspension when warm than it will when cold. Just like the air can hold more water vapor in suspension when the air is warm. Let warm saturated air become colder and the water vapor will precipitate into rain and fall to the earth.

Now there can be free water that is sitting at the bottom or a gasoline tank and there can be dissolved water that is suspended in the gasoline. Hopefully the Racor or other water separating filter will catch the free water. Any water that is suspended in the gasoline will flow on to the motor and be burned without doing any harm.

Now leave a batch of ethanol contaminated gasoline to sit idle for a number of months, with the tank breathing moisture laden air in and out daily, and with the coming of the cold winter temperatures their is a greater liklihood of phase separation occurring where the water and the ethanol stop being dissolved in the gasoline and drop to the bottom of the tank. Get that crap all the way to the motor and it will not be a pretty site. I was so anal about this that every time I stopped using my boat for more than a few weeks at a time I pumped all of the gasoline from the tank and put it into my truck. Added fresh fuel then whenever I next visited the boat. Was not particularly burdensome but most are not going to do that.

I agree 100% with your assessment of E fuels being rammed down our figurative throats.