Fuel tank water removal for nervous types

C

Ctarmigan

Member
Hello all,

Having recently solved (hopefully?) a water-in-fuel-tank problem, I thought I’d document here in case it’d help others.

Quick background: during spring prep this weekend, I replaced my Racor filter. On filling the dry filter from my starboard tank, I collected lots of water (50:50) in the filter bowl. Bad news.

Water Removal Steps:

  • 1) Access the fuel tank – I unscrewed the fuel pickup tube on the starboard tank, and pulled it out of the tank. Stuck a little at the bottom of the tube, but with some of patient wiggling I got it out of the access fitting.

    2) Tilt the tank – I dropped the tongue as low as I could with the jack, and then raised the rear starboard corner of the trailer, and supported securely with a jack stand. Now the lowest part of the starboard fuel tank was roughly below the fuel pickup tube access I’d opened up.

    3) Suck out the water – I’ve read a lot online about using a 12V fuel pump to suck fuel out of a tank. I’m a chicken – I don’t like mixing gasoline and electricity outside of an engine block – so I opted for a non-electric option. I used a manual fluid transfer pump (https://www.canadiantire.ca/en/pdp/motomaster-fluid-transfer-pump-0283047p.html) to pull water/fuel from the bottom corner of the tilted tank, and transferred into a clean 5 gallon bucket. A little slow – it would take quite a while to empty a full tank – but by the time I’d extracted ~5 litres it seemed I’d removed all the water, and was just sucking up plain gasoline.

    4) Try the port tank – I tried the same approach with the port tank, but found I couldn’t remove the fuel pickup tube because of some dinged up threads. Not interested in reefing too hard on it, and risk tearing it out of the plastic tank entirely, I looked for a different option. Chose to remove the fill vent hose instead – it came off easily, and the tilt I’d already put on the whole boat meant the low end of the tank was pretty close to that access point anyhow. Extracted ~5 litres of fuel using my same fluid transfer pump, with no water visible. Water seemed like just a starboard tank issue, but I was glad I checked.

    5) Clear the lines – I assumed there was still some water tucked away in the lines from my starboard tank to the Racor filter. To clear this, I alternated filling and draining the Racor bowl until it stopped receiving water in the fuel. To refill the drained Racor bowl each time, I opened the ball valve at the motor end of the fuel line with a finishing nail, and pumped the bulb, draining the fuel into a small container. The Racor bowl filled quickly as I did this. I expect there’s an easier way to do it than I did (e.g. opening the vent on the Racor filter fitting – but I couldn’t find my Allen key set). I also tried the port lines, but found no water there.

I believe now I’ve removed (nearly) all of the water from the bottom of my starboard tank, and identified no water in my port tank. I smell like a refinery, but at least the issue’s dealt with.

Couple questions for the pros here:

  • 1) Having delivered a slug of water to my new Racor filter, should I replace it?

    2) Should I add some gasline antifreeze (e.g. Heet) to deal with any small amount of remaining water in my starboard tank (or just rely on my Racor to keep it out of my outboard)?

Sorry - no photos of my progress; didn't want to be fiddling with my cell phone while surrounded by gasoline fumes, either.

Oliver
 
I would absolutely replace my filter, and buy two so I would always have an extra on the boat. I have no input on HEET, as I have never used it…..good luck to you! I hope this solves your issue!

-Mike
 
Hi Oliver,

I have heard of pitting on aluminum tanks that led to water getting into them. Also, it may be the fuel sender gasket is old and not sealing properly and so water is getting into the tank. Maybe the fuel vent is not positioned (turned) correctly, thus allowing water spray to enter.

Looking forward to hearing from you when you figure it out. :)
 
I've certainly been putting my thoughts to water source, an ounce of prevention worth a pound of cure, after all.

On further inspection, fuel fill cap o-rings are in good shape; I don't see them admitting any water. A good check, though, and I'll continue to give them a look at each fill.

Could have been an ethanol issue, though I'm pretty careful to find ethanol-free fuel, and it wouldn't easily explain water in one tank and not the other.

Water splashing up into the fuel tank vents? A definite possibility - Sunbeam has a beautiful thread that carefully documents his vent upgrades (http://www.c-brats.com/viewtopic.php?t=19284&postdays=0&postorder=asc&start=30), and that job's on my long list. In the meantime, I run with rubber crutch feet stuck over the vents to prevent water entering, but they have fallen off on occasion - maybe the water source?

Ultimately, though, this could have been longstanding issue I'd only noticed now. The boat's on the trailer in my shop, and I'd lowered the tongue to level out the trim fluid reservoir so I could top it up. Bow down, any water pooled at the bottom of the tank may have collected where the fuel pickup could get a much heartier gulp of it than at the hull's operating attitude.

Considering what to do with the new Racor filter - my current plan is to keep it in place, at least for the next couple tanks of fuel. I'll save myself a replacement in case there's yet more water to deal with; once I'm confident my tanks are dry I'll consider replacement. I do carry a spare on board, and can swap out if the need arises in the interim.

Still happy to take advice; I've got nothing on the collective here.

Oliver
 
To prevent water in the boat tank, and everything else, I use STP Gas Treatment. It's cheap and it must work, as I've not found water in any filter change when I've used it. I believe it emulsifies the water so it can pass through the filters and injectors and be burned.

When we first got Journey On, I filled up at a gas station, right off I-5, north of Portland. The motor lost power, ran rough, etc. Pulled the filters in the motor as well as the Racor and found water and a white deposit. Changed the filters, added a bottle of STP Gas Treatment and everything has been fine since.

I also use STP Sta-Bil (?) after every summer, when the boat use slows down. No problems starting up after the layup.

Boris
 
Water splashing up into the fuel tank vents? A definite possibility - Sunbeam has a beautiful thread that carefully documents his vent upgrades (http://www.c-brats.com/viewtopic.php?t= ... c&start=30), and that job's on my long list. In the meantime, I run with rubber crutch feet stuck over the vents to prevent water entering, but they have fallen off on occasion - maybe the water source
Click to expand...

Years ago I had incidences of water in the fuel that kept recurring until I addressed the fuel vents. Since then, no more water. As for alcohol to disperse water in the fuel, I do not do that anymore. Like you I use no ethanol fuel which fortunately is available where I am.
Again, years ago the Oregon State Marine Board published a warning of the effects of ethanol in fuel doing damage in the marine environment. Turns out I was having work done at Gregs Marine in Garibaldi OR.( 90 horse with 4 carburetors). By coincidence he was featured in a video on the Marine Boards site warning of the dangers of ethanol in fuel, particularly in a high humidity climate, ie.OR coast. He brought out a little glass jar with fuel in it, shook it and it looked like a Christmas snow flake scene of aluminum flakes. He said this fuel came from a local aluminum fuel tank. He went on to say if I understood him correctly is that alcohol in the fuel absorbs moisture from the ambient air, particularly in a high humidity environment in winter on the coast here. He said once there is enough moisture in the fuel that the alcohol can no longer absorb it, then a chemical reaction can take place that is caustic. He mentioned that this is not just affecting aluminum fuel tanks. An owner with a brand new Yamaha in Astoria had significant damage occurring if I recall correctly within its first or second year. The take away for me was, NO more ethanol fuel when possible.

Aside from the ethanol issues, he also recommended Stabil or equivalent. He said for winter/longer term storage, he recommended tripling the Stabil then disconnecting the fuel line, and running the motor until the carburetors were empty. He said that the Stabil put a light protective coating on the carbs, so there wasn't the crusty crud occurring in the spring that most of us have experienced in an outboard or yard engine (both for me until Stabil). He said he used Stabil in all his home engines, generator, weed whacker, etc.
 
Follow-up:

Shortly after posting this thread, I swapped out the stock fuel tank vents with the Attwood stainless steel flush mount vents referenced in Sunbeam's vent replacement post.

Fast forward to the present day (3 years on) and I had recent occasion to remove and fully drain both fuel tanks. I'm happy to report there was zero water in either of them.

Full points to the Attwood vents (and Sunbeam's detailed replacement log - thanks!).
 
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