Water Separators

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curtdawg88

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Who uses a water separator? I just bought a 40hp 4 cylinder 2 stroke Mariner that doesn't have one on it. I have buddies that tell me I need one. Are there any Cons to having one? Thanks!
 
There are no 'cons' to a water separator, that I can think of. It will,however, have to be taken care of.

Over a period of time it will probably fill up with water. If you get a load of contaminated fuel, or, if you have a bunch of moisture accumulate over a period of non-use, then you can get more water through the separator than it can hold.

Some of these have a spin on element. Some have a see-through bowl with a drain. Either way, water won't get to your engine if you pay attention to the separator and maintain it.

I found this info to be helpful:https://www.fuel-testers.com/remove_water_gas.html

Boating Magazine published this article:https://www.boatingmag.com/how-to/installing-fuel-water-separator
 
Ethanol in gas will absorb moisture, but that's usually not an issue on small tanks that get used and refilled a lot. Where it will really save your bacon is if you gat a batch of bad fuel. For the benefit vs what one costs, I would not be without one on an outboard. On the newer motors, water is death to injectors.
 
The one main thing to remember about a water separating fuel filter is that once water fills the canister/filter assy. to the point that it touches the filter element.....it will be sucked into your engine. The separator is only as good as the person maintaining it.
A water separating filter is just a canister having a filter element elevated well above the bottom of the canister thereby allowing water to accumulate at the bottom of the canister.
 
Pappy once again hit the nail on the head. They're only as good as the person who maintains it.

One thing that I think is beneficial is a new style EPA compliant fuel tank. They are sealed; no vent. At first I hated them with a passion. Couple years ago I did an experiment to see what their purpose it. I took 2 one quart mason jars and filled them both halfway with gasoline (no oil, no ethanol just gas). Verified ethanol content with test strip to be lower than 1%; as the place that sells us our fuel advertises "no ethanol". One jar I put the lid on. The other I left the lid off. In 2 hours time, the lidless (vented) jar lost about 40% of it's fuel volume while the non-vented jar didn't lose any. But the lid was tight; when I removed it, it had some pressure. Also, in the vented jar, I could see WATER in the bottom of the jar. How on earth? It didn't have water in it when I poured it in? Well....fuel (along with other liquids) will lose heat as it evaporates; I noticed that the jar was cold to the touch. On a humid day like it was that day, the fuel jar cooled to the point where moisture would condense in the fuel. The fuel actually got cloudy because of the condensing moisture. By the next morning, about 60% of the fuel was gone and there was a few ounces of water in the bottom. Let it sit another day and nothing more had happened; same volume, same water in the bottom.

Point being, a vented fuel tank can do the same thing; allows fuel to evaporate, which causes evaporative cooling, which draws in condenation. I could see with a 6 gallon fuel tank (as opposed to 1 quart jar) it could draw in a lot of moisture. It was at that point that I went ahead and bought a new 3 gallon EPA compliant (low permeation) fuel tank. $65 but fuel doesn't evaporate. Plus since the old 3 gal tank was basically 4 weeks old, I put it on CL and sold it for $30 cash and recovered some of what the new one cost. Lot of people still hate the new tanks and I understand why; but there is a purpose to them.

Verified that purpose with a factory Yamaha rep.
 
Do not understand how these new tanks work.Surely air must enter the tank to replace the fuel and wouldnt this air contain some moisture?
 
I've got a 10 micron filter on mine. It will desperate the water also. And as above, it only matters if you maintain it. Which reminds me....its about that time.
 
I have not yet owned an EPA tank. If I am not mistaken, the new EPA tanks have a valve allowing air into the tank under vacuum. The tanks will not vent pressure out. The EPA tanks have this valve in the cap. The earlier tanks had the valve built into the pick-up module. Again, if I'm not mistaken, this is the only difference. I too automatically hate anything mandated by bureaucracy.

All the plastic OMC tanks from the late 80s & 90s had a similar setup. Running the motor would draw fuel from the tank creating a vacuum. Pretty soon you would hear a little whiny-wheeze from the tank pick-up module as the vacuum-valve let a little air in. If you let the tank sit in the sun, the pressure would build up and the tank would inflate. The weak part on these tanks is the pick-up module. It's plastic. The sun cracks them and they will seep fuel through the tiny cracks as soon as any pressure builds.

The steel tanks were similar. They would hold pressure, even when you plugged the line onto it. The line fitting would open the 'vacuum' valve that would let air in if/when a vacuum condition developed. Most of the old steel tanks now leak through this vacuum vent system whenever you plug the line on. The rubber seal inside deteriorates and allows pressure to leak through when the line is plugged onto the fitting. This results in fuel leaking around the fitting area. Everyone replaces the mounting gasket but that's not the problem.

All the tanks with the automatic vacuum vent systems have given me grief sooner or later. I don't yet know about the EPA tanks. Haven't owned any yet. It might just be the way to go. Costs $100 to find out.

The 'cheap' versions of all these earlier tanks have no gauge, no auto vent, and a permanently attached hose. No problems with these tanks. They have a manual vent in the cap that requires operator input...but the tanks are reliable. I just have to remember to open it when I start out, and close it when I'm done.

Tank you for your time.
 
I was looking at a couple of water separators earlier today. I've got a fuel can with premixed gas/oil in it and yesterday I poured about 24 oz. of it (after shaking it up) into a squirt bottle. After sitting overnight the bottom 1/2" was all water. That is scary thinking of it going thru my OB carb. No wonder it stopped working when I was on the Chattahoochee river.
LOL add insult to injury I capsized the boat, (after it stopped running) the motor was under water for an hour or so, so now it's been in the shop for a month waiting on them to go thru it and do what they can to make her work again.
I may have a small boat and small motor but I believe I'm gonna put a water separator on it just to be on the safe side.
 
Did that tank of fuel go over into the river with you? That's a large amount of water in there.

Has your engine been sitting at the dealer un-serviced after it was submerged?...or did they get right to it? A submerged engine needs to be serviced immediately or it can turn into a one-piece sculpture. I would take issue with any shop that lets a submerged engine wait.
 
It's be sitting unserviced. After nearly 4 weeks I went in to check up on it and they still hadn't done it. Told me they may have it done by this coming Monday. Really starting to tick me off. Feeling like because I'm a little peon with no big boat or big motor that I'm not important enough to deal with.
I had considered possibly trying to buy a boat there but having other thoughts on that idea.
I might be wrong on my feelings about it all, but just the same, it's the feelings I have at the moment.
BTW, guys, thanks for your heads up on a dealer that doesn't get right on it after being submerged.
 
I work with aircraft fuel trucks and on a tank farm and I am in a constant battle against water in fuel. Fuel can get water in it from condensation inside of the tank due to temperature changes. We keep the tank trucks as full as possible to keep condensation at a minimum. Full tanks do not attract condensation as much as an empty tank would. We also drain and take samples every day of the fuel. We have low point drains to drain the tanks and we also take samples from the filter/separator vessels while recirculating fuel in the trucks. The filter/separator vessels have separator elements that are designed to prevent water from getting through but allow fuel to get through. The water is collected in a sump at the bottom of the vessel. We drain this sump daily. We also test every truckload of fuel that comes in for water before we accept the fuel which may be twenty loads a day. We use a "white bucket" and hydro-kits for these checks. As for the white bucket, if there is any significant amount of water it will settle to the bottom and you will see it. The hydro-kit can check for water at less than 5 parts per million. Your boat tank can attract water in the same way. If you have a tank that is 1/4 full and it sits for a month with frequent temperature changes it will condensate. Another thing to remember is that service stations have water in their tanks. I used to drive tankers and would see 3-4 inches of water in the tank as normal. Some would have as much as 10 inches of water in them. We used water finding paste when we would stick the tank to check how much water was in them. For this reason you do not want to fill your tank while there is a tanker dropping a load of fuel at the station. As the fuel is being dropped it is stirring the tank up and sending water to the pumps where you are pouring it into your tank. I will not even fill my vehicle while a tanker is dropping a load of fuel for this reason. As they say "All fuel water in it". You can't eliminate it but you can keep it to a minimum.
 

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