Water Separator for outboard

[steve77]

While trouble-shooting my Nissan 5 hp four-stroke, I found water in the gas tank. I see Defender sells a fuel filter/water separator manufactured by Unikas. It looks to me like this needs to be permanently mounted vertically to work, very similar to the Racor unit I have on my auxiliary. Not sure I like the idea since I regularly remove the fuel tank from the dinghy.

Part of the problem is I don't use the dinghy all that much. We may go for a ride once every two or three weeks. Therefore, fuel can sit in the tank for two or three months before I add more.

I understand that running the engine more and using the gas quicker will help. But I can still see the day when I buy some bad fuel at some remote location and don't want to clog the carb. Right now, all I have is the little bitty filter installed on the engine prior to the fuel pump.

What do the rest of you do to keep water and dirt out of the engine?

Cheers,
Steve

[thinwater]

e-10 or plain gasoline? it makes a huge difference. If it is e-10 and phase separation is the issue, no seporator will help (the volume of phase will be too large + other issues). If it is e-10 keeping the vent closed EVERY time you stop running will keep the humidity out.

If it is plain gas the issue may still be the vent. Are you closing it before it rains, for example?

Be thankful you have a portable tank; having a vent you can close is a big help.

[steve77]

Well, this is gasoline purchased at the local pump. It has a sign that says it may contain up to 10% ethanol, so I suppose I have E10 in the tank.

[colemj]

We use one like this:
Honda Spin On Fuel Filter (this is a Honda brand, but it is made by Racor and sold under different brand names also).

It is very small and easy to find a place to mount. Alternately, you can get larger spin on ones for probably less money.

This one does need to be permanently mounted vertically, but it is very small. I don't understand why it would be a problem if you regularly remove your engine and gas tank? The filter just stays permanently attached to the dinghy - pull the fuel hose connectors off the engine and tank and you are all set to remove them. Unless you also want to remove the fuel hose itself, then that would be more problematic.

Nobody should be running an outboard without an external fuel filter/water separator. Almost every single one of the outboard problems I run across would not be a problem if they had an external fuel filter. The smaller the outboard, the more important this is.

Mark

[S/V Antares]

Keep a turkey baster handy and suck up a few cups off the bottom of the tank every once in a while. Put it in a clear water bottle and let it sit for an hour or so. You will see any water or phase separation. If it looks good put it back in the tank.

[steve77]

Thanks, colemj. The Honda spin on filter is similar to the Unikas unit in that it needs to be mounted somewhere vertically, like on the transom of the dinghy. When putting the dinghy away, I remove the engine and tank. Either I have to leave the external fuel filter mounted on the transom, or find a way to make it easy to remove. Right now, I am looking at the latter.

Maybe I'll look at some simple brackets that can be mounted on the transom, and the "ears" of the separator slip behind the bracket to hold it in place. That may make for a good solution.

Cheers!

Steve

[ranger58sb]

Steve, I've thought about mounting an external fuel filter within a portable box of some sort. One of the small plastic waterproof boxes, perhaps, or maybe a small battery box.... or Mark once suggested a small cooler might be a useful option. Anyway, that would mean the whole box, fuel filter and all, including fuel lines, could be easily removed or installed.

Haven't yet gotten a round tuit, though

There's also a snap-on Racor filter, larger than what you've looked at., but perhaps easy o work with: http://www.parker.com/literature/Rac..._-_RSL0154.pdf

See also here, post #82 and subsequent: http://www.cruisersforum.com/forums/...d-94204-2.html

-Chris

[steve77]

Chris - That looks like a pretty cool setup. I'll look into that Racor unit. The snap-in feature will make it easy to remove the filter when I remove the tank from the boat.

Thanks for the suggestion.

Cheers!

Steve

[thinwater]

I've studied this extensively (I'm in the refining industry) both at the refining level and in boats (for articles). You're chasing your tails, thinking that a separator will help with e-10. It is a different animal than gasoline.

1. If there is less water than the e-10 can hold there will be ZERO drop out. A separator will catch nothing because the e-10 will absorb the water.

2. If there is more water that the gasoline can hold, 10% of the volume will fall out and the separator will be completely overwhelmed; it can't hold 1/2 gallon.

Focus on what will work; keeping the vent closed when not running. Take this one precaution and this will never happen. I didn't used to; problems every time it rained or I was away too long. Started closing it every time; not a problem in many years. The water is NOT coming from the gas pump nor appearing magically. You are letting it into the tank. E-10 is not that hard to use, you just need to understand how boats are different from cars (free vented vs. controlled venting).

I do agree that an extra filter is a good idea, particularly for small engines that don't have one (only an in-tank strainer). Adding a small in-line filter is great.

[colemj]

Originally Posted by thinwater

I've studied this extensively (I'm in the refining industry) both at the refining level and in boats (for articles). You're chasing your tails, thinking that a separator will help with e-10. It is a different animal than gasoline.

1. If there is less water than the e-10 can hold there will be ZERO drop out. A separator will catch nothing because the e-10 will absorb the water.

2. If there is more water that the gasoline can hold, 10% of the volume will fall out and the separator will be completely overwhelmed; it can't hold 1/2 gallon.

Focus on what will work; keeping the vent closed when not running. Take this one precaution and this will never happen. I didn't used to; problems every time it rained or I was away too long. Started closing it every time; not a problem in many years. The water is NOT coming from the gas pump nor appearing magically. You are letting it into the tank. E-10 is not that hard to use, you just need to understand how boats are different from cars (free vented vs. controlled venting).

I do agree that an extra filter is a good idea, particularly for small engines that don't have one (only an in-tank strainer). Adding a small in-line filter is great.

I agree if you get your gasoline from the corner Esso station that water is not coming from the pump. If, however, you get your gasoline out of a plastic jug from behind a guy's house on a small island, water is a fact of life.

This water isn't always apparent, and it sometimes accumulates without you knowing. With a water separator with a transparent bowl, you see the problem in time. Even if you do not, the water does not get through the filter and the engine stops from lack of fuel. This is much better than the alternative.

The best part of a water filter is that it also filters fuel, which is another bad actor in cruising destinations.

Our fuel tank is kept inside an igloo cooler and it is one of the new tanks that stay pressurized, so I know water isn't coming in from the vent cap.

However, I need to drain water out of the fuel filter quite regularly.

Outboards out here can be put in two categories - those having almost constant problems and those having almost no problems. Those categories are also coincidental with not having a fuel filter/water separator and having one.

Mark

[ranger58sb]

Originally Posted by thinwater

2. If there is more water that the gasoline can hold, 10% of the volume will fall out and the separator will be completely overwhelmed; it can't hold 1/2 gallon.

Perhaps the percent of the small amount of gas we carry at any given time -- usually 1 gallon or less in the outboard's fuel tank -- especially if it hasn't reached that full 10% amount yet, would maybe fit in the separator bowl. Enough to be noticed, drained, remaining gas swapped out to a car or whatever...

I think...

-Chris

[colemj]

Originally Posted by ranger42c

Perhaps the percent of the small amount of gas we carry at any given time -- usually 1 gallon or less in the outboard's fuel tank -- especially if it hasn't reached that full 10% amount yet, would maybe fit in the separator bowl. Enough to be noticed, drained, remaining gas swapped out to a car or whatever...

I think...

-Chris

Even if it is a lot of visible water and you don't notice it, the worse that happens when you have a filter/separator inline is that it fills completely with water and blocks fuel to the engine so your engine dies and you learn to first look at the bowl before considering other causes. Drain the bowl and tank and you are good to go again.

Without that filter/separator, you suck water into the engine itself and have more problems than simply draining the water out of the tank.

Mark