Perpetual wet fuel tank???

D

Drewski Canuck

Active Member
Yesterday I pumped out the fuel tank, and as suspected, the "fuel" at the end, was very clear in colour. Seems to happen every few years. No matter if using sea foam, Isopropyl, fuel stabilizer, it happens.

The tank has no leaks, but I get the feeling that leaving a part full tank for longer periods is resulting in condensation issues. I have used a fuel seperator on the fuel line, and it has worked, but when the tank is in the wet state, it is a constant chore to empty the bowl when the fuel stops flowing.

Has anyone on here found a magic bullet to stop this from happening?

Drewski
 
Drewski Canuck said:
Yesterday I pumped out the fuel tank, and as suspected, the "fuel" at the end, was very clear in colour. Seems to happen every few years. No matter if using sea foam, Isopropyl, fuel stabilizer, it happens.

The tank has no leaks, but I get the feeling that leaving a part full tank for longer periods is resulting in condensation issues. I have used a fuel seperator on the fuel line, and it has worked, but when the tank is in the wet state, it is a constant chore to empty the bowl when the fuel stops flowing.

Has anyone on here found a magic bullet to stop this from happening?

Drewski
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Salt or fresh water in fuel, Are you using a non ethanal fuel?
 
Methyl hydrate I would be adding in as well, but sounds like you have something going on if you have that much moisture building up in your tank/fuel.
 
How much water are you talking? ive always been told fill the tank and add fuel sta bill or drain i out as much as possible I do the first start adding fuel sta bill last 2 weeks of my season and fill it up as I know by next year the gas prices will jump!!!
 
Lots of previous threads and discussion on the water in fuel tank issue. Sounds like you are getting a lot more than one would expect from a little internal tank air condensation. Most likely cause for considerable water in the fuel tank is sealing failure at the filler cap assembly. It is also worth checking to see that the tank air vent in the side of the hull has not turned so that the opening is more exposed to rain, spray and waves.
 
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The water problem may not seem like a big deal, but when a pocket of "wet" fuel goes through, and "I am running WOT, it sputters until the bad gas passes. The source of the problem may be buying fuel when it dips and holding it for as much as 6 months at a time, but if I had to say how much water in the tank, I would say 1/2 an ice cream pail of "clear" gas on pump out, at the bottom of the tank. Regular gas has been run, with the associated ethanol, so from here forward I will go with only ethanol free premium.

I know Cummins sells a water gathering "lace" that you put into the fuel tank fill. It swells, you pull it out. I may have to try that next.

Drewski
 
Drewski Canuck said:
I would say 1/2 an ice cream pail of "clear" gas on pump out, at the bottom of the tank.
Drewski
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Your problem is not due to condensation. Too much water. There is water getting into your tank from somewhere......storage containers or possibly gas cap or vent as mentioned.
 
I totally agree with Rockfish and Gunnerlove: not condensation (myth) and certainly water intrusion from either fuel filler (most likely) or the vent. This is a big issue and will overwhelm filters and damage injectors. I know firsthand.

Never use alcohol additives or ethanol-laden gas, either. The water WILL precipitate. It's a disaster waiting to happen - your main engine quits 25 miles from Port and you then have a very long, cold, wet day getting back on the kicker. Again, how do I know?
 
Foxsea said:
I totally agree with Rockfish and Gunnerlove: not condensation (myth) and certainly water intrusion from either fuel filler (most likely) or the vent. This is a big issue and will overwhelm filters and damage injectors. I know firsthand.

Never use alcohol additives or ethanol-laden gas, either. The water WILL precipitate. It's a disaster waiting to happen - your main engine quits 25 miles from Port and you then have a very long, cold, wet day getting back on the kicker. Again, how do I know?
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And that’s only if your kicker runs off a different fuel tank. You’re screwed if your using one tank for all fuel!
 
Corey_lax said:
And that’s only if your kicker runs off a different fuel tank. You’re screwed if your using one tank for all fuel!
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Exactly! ... and by the time we got in on the little 8 h.p. kicker, it was sucking fumes. Our fuel filler was very poorly placed in the "splash" well. It leaked. Why would a reputable builder do that??? Very quickly afterward, it was relocated high and dry.
 
Corey_lax said:
And that’s only if your kicker runs off a different fuel tank. You’re screwed if your using one tank for all fuel!
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You may not necessarily be screwed.

My replaced tank is bone dry when it comes to water and we seldom see any in the Racor separators. Both the big 225 and the 9.9 have their own pick up tube off the single large tank and their own Racor.

I don't expect it to ever happen but if somehow the big motor were to be shut down because it was getting some water we may not necessarily be screwed on the kicker. First the kicker is carbed, so less susceptible to being affected or damaged by water than injected motors. The big motor would be far more likely to mix the fuel with the water as the boat would be bouncing around and angled up more, even at slower speeds, and certainly on plane, even with the baffles in the tank controlling fuel sloping around in the tank. The pickup tubes are at the back of the long tank closer to the motors so that if the bow and tank is up angled like when you are on plane there will be more water at the back of the tank for the pick-up tube to suck. With the kicker cranked up the boat still stays flat on the water and the water would tend to be spread out and stay below the fuel so less likely to suck it up. Our tank up tubes do not go all the way to the bottom of the tank to allow a little water and dirt for that matter to be in the bottom of the tank with a decreased chance it would be sucked up. Thinking about it, it may not be a bad idea to cut the up tube for the kicker just a little shorter than the one for the main so that if the main begins sucking water off the bottom of the tank, the kicker as your back-up motor would be less likely to.

Finally, if the main motor is down because of water in the fuel, the first thing we would do is check the kicker's Racor water separator visually and if no water, no problem, otherwise drain it and then assign the crew to watch the fuel separator constantly and if it starts showing water we could periodically drain it as necessary as it is up high in the bilge with access to get a container under it. Not a fun job, but not my job, I am steering the boat, and they are younger and in better condition. I think most likely, that even with a gallon or so of water in the fuel tank we could nurse the boat back to port on the kicker, especially if it was not super bumpy and mixing the fuel and water more. The tank is about 75 us gals and I have never come back into home port with it less than 60% full and often much more, which also helps. With lots of fuel in the tank it should not take too long to remove the tank deck cover, then remove the kickers down tube and cut it off higher up and screw it back in to keep it away from the water in the bottom of the tank. That would be a last resort pain in the butt job at sea, but anything to get you back to port.
 
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Separate kicker tank and lines FTW. I alao try to avoid filling main and kicker tanks in the same trip to fuel dock or gas station. If I get a dose of bad fuel, say from water collected in a depleted fuel dock supply tank, at least only one motor is affected and I still make it home.
 
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