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Author Topic:   Water in Fuel--Again

rjc1982 posted 05-22-2014 05:45 PM ET (US)
[Six] months ago I had to drain and flush the fuel system on my 170 Montauk because a serious amount of water was in my tank. Last weekend my motor died, and, after pulling a fuel sample, I found [the fuel] to be almost 50-percent water. My fuel tank is the orignal (Moeller I believe) 24-gallon located under the RPS. I also have a Sierra 90-micron water separator and add fuel stabilzer religiously. Since my problem last fall, I have been keeping the tank full to the brim. I was told that reduces the chance of condensation developing in the tank. How could I possibly have that much water in my tank again after only six months? I've been told it's just a matter of the humid climate here on the Texas Gulf coast, but I can't believe that's the only cause. I think the vent on the fuel cap may not be sealing properly. Any thoughts as to what might be going on here? Thanks in advance.
ANDREW PITCHFORD posted 05-22-2014 06:08 PM ET (US)
After the fuel tank has sat on a hot day, when the tank vent is opened to you hear a hiss or pressurized air moving?
contender posted 05-22-2014 09:25 PM ET (US)
Are you purchasing the fuel in the same place, is your boat kept in the water, fuel cap tight? Getting this much water in a tank can only come from a leak or water in the gas to begin with. Or some one is screwing with you stealing your gas and filling it with water. I'm in S Fla and there is more humidty here than anywhere (except maybe the jungle of S America) I never have this much water in any of my tanks...
rjc1982 posted 05-23-2014 09:56 AM ET (US)
Thanks for the replies. I do buy my gas at the same place every time, and usually fill my truck while there so I don't think that's where the water came from. Could the water be getting in aroung the gas cap or outlet fitting when I'm washing down the boat? I'm really beginning to think that the cap or the seal around the outlet fitting may be my problem. Anyone heard of those two being an issue in the past?
deepwater posted 05-23-2014 07:20 PM ET (US)
If you can top off the tank after each trip there is less room for water. The liquid gas will only expand so much as the empty area fills with gas vapor during the hot day and sucks in moist air at night.
contender posted 05-23-2014 10:18 PM ET (US)
If your cap is bad then yes, you could be getting water in from the cap, but I think you have another problem, its not like you hold the hose on your fuel cap when you are cleaning the boat, you are getting water from another place as well...
deepwater posted 05-23-2014 11:48 PM ET (US)
The tank, if on the deck for four days of heating and cooling along with fog or rain, could add lots of water to the tank. Topping off the tank reduces that.
RandyV posted 05-25-2014 04:01 PM ET (US)
I had the same tank in my Montauk. If your tank top is concave as mine was rather than flat like it is supposed to be so it would normally shed water, water will tend to sit where the tank hardware is mounted. If that seal is bad, you could get a huge amount of water in your tank. I was always concerned with that seal but stored my boat indoors and with it under the RPS during use. I made sure water was not puddling on the top of the tank.
Empty the tank, spray that area with a garden hose then check to see if you have new water in the tank, or just replace the seal. The amount of water you are seeing in such a short amount of time can't be from normal condensation.
Ridge Runner posted 05-25-2014 08:43 PM ET (US)
The cap is "self venting" the original cap has been known to have problems and not last very long. My cap lasted only two seasons. Replace the cap.
Kelch has a retail website BlueSkies - http://bluskies.us/fuelguages.aspx
The replacement gauge is vented 2-3/4-inch threaded cap with a 12-1/4-inch float depth Kelch part number #7J203085 / BlueSkies part number #BK0130002; cost is $23.45.
If you meant 50-percent of the tank is water - 12 gallons - that is a massive amount of water - and I can't believe that much water could get in the tank even if you had no cap on it at all/ If you meant 50-percent of the Sierra filter is water that very well could be the cap.
rjc1982 posted 05-25-2014 09:33 PM ET (US)
I drained the tank, fuel lines, filter bowl and carburetor bowls. Replaced the the fuel cap, water separator and fuel filter. Motor started, ran for a few minutes then died. Acts like it wants to start but I can't get it running. Is there something else I need to do after having all that water in my fuel. It's a 2004 Mercury 90 Fourstroke.
contender posted 05-25-2014 09:44 PM ET (US)
Easy things to check are vent open and fuel bulb OK. I would try using 6-gallon remote tank, change the plugs, clean them, try a little starting spray. How is your fuel pump? Did you clean it out? Is your battery at a high charge (motor needs to turn over fast). Good luck
rjc1982 posted 05-25-2014 09:53 PM ET (US)
Vent was open and primer bulb pumped up til hard. Did not drain or clean out the fuel pump. Will replace the plugs and see what happens. Thanks.
jimh posted 05-26-2014 11:30 AM ET (US)
According to the theory of magic water creation by diurnal temperature variation and condensation in fuel tanks, you should put your 12-gallon tank out in the sun for a few days and it would rapidly fill with pure water. I would keep this tank as a good source of fresh water. What if you were stuck offshore for a few days with a disabled engine--a very likely possibility in your case. This magic fuel tank that makes water all by itself could be, quite literally, a life saver.
As you might infer, I am being sarcastic. Seriously, there is no way condensation from diurnal temperature variation is making 6-gallons of water in your on-deck fuel tank. The water is coming into the tank in only two ways:
--the water comes in with the gasoline you are buying, or
--the water comes in via a leak on the top surface of the tank
A tank leak is not typically unidirectional, so if the water can get into the tank from outside, the gasoline could get out from inside. Turn the tank on its side and see if gasoline pours out from the cap or fuel pickup fitting.
deepwater posted 05-28-2014 05:40 PM ET (US)
A very hot tank with at half-full and subjected to a sudden downpour of cool rain could suck up a fair amount of water through the vented cap. amd repeated every day you might get several cups. The use of a tank would be ok. Fill with saltwater expose to sun and condense the vapors in a small cup.
rjc1982 posted 05-30-2014 01:40 PM ET (US)
Do y'all see any concern or potential problem in trying to clean out my carbs by running the engine off a separate small tank with a gallon of fuel mixed with a full bottle of solvent like Quickleen or Seafoam?
jimh posted 05-31-2014 09:51 AM ET (US)
I do not recommend making up your own Witch's Brew of fuel and additives with concentrations in excess of those recommended by the engine maker. I prefer to use the fuel additives recommended by the engine maker and at the concentrations recommended for those additives.
rjc1982 posted 06-02-2014 03:32 PM ET (US)
Hey All, I wanted to post a follow up on this issue with the results. I found 2 items that were allowing the water into my tank. One was the vent on the fuel cap, it was not sealing properly when closed. I'm sure that moisture from the air was getting into the tank there. The other was the o-rings around the fuel outlet fitting. I wash my boat thoroughly after each trip and that fitting was surely allowing a large amount of water enter the tank. After replacing both suspect items I drained and cleaned the tank, replaced my fuel separator,fuel filter and spark plugs then drained the carb fuel bowls. Motor fired right up and seems to be good to go now. Thanks for all the replies to my message.
deepwater posted 06-03-2014 02:37 AM ET (US)
That's nice to know
boatdryver posted 06-03-2014 09:31 AM ET (US)
rjc, thanks for taking the time to post the final diagnosis. doesn't happen always.
JimL
contender posted 06-03-2014 05:27 PM ET (US)
Yeah its good to know the outcomes

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Author	Topic: Water in Fuel--Again
rjc1982	posted 05-22-2014 05:45 PM ET (US) [Six] months ago I had to drain and flush the fuel system on my 170 Montauk because a serious amount of water was in my tank. Last weekend my motor died, and, after pulling a fuel sample, I found [the fuel] to be almost 50-percent water. My fuel tank is the orignal (Moeller I believe) 24-gallon located under the RPS. I also have a Sierra 90-micron water separator and add fuel stabilzer religiously. Since my problem last fall, I have been keeping the tank full to the brim. I was told that reduces the chance of condensation developing in the tank. How could I possibly have that much water in my tank again after only six months? I've been told it's just a matter of the humid climate here on the Texas Gulf coast, but I can't believe that's the only cause. I think the vent on the fuel cap may not be sealing properly. Any thoughts as to what might be going on here? Thanks in advance.
ANDREW PITCHFORD	posted 05-22-2014 06:08 PM ET (US) After the fuel tank has sat on a hot day, when the tank vent is opened to you hear a hiss or pressurized air moving?
contender	posted 05-22-2014 09:25 PM ET (US) Are you purchasing the fuel in the same place, is your boat kept in the water, fuel cap tight? Getting this much water in a tank can only come from a leak or water in the gas to begin with. Or some one is screwing with you stealing your gas and filling it with water. I'm in S Fla and there is more humidty here than anywhere (except maybe the jungle of S America) I never have this much water in any of my tanks...
rjc1982	posted 05-23-2014 09:56 AM ET (US) Thanks for the replies. I do buy my gas at the same place every time, and usually fill my truck while there so I don't think that's where the water came from. Could the water be getting in aroung the gas cap or outlet fitting when I'm washing down the boat? I'm really beginning to think that the cap or the seal around the outlet fitting may be my problem. Anyone heard of those two being an issue in the past?
deepwater	posted 05-23-2014 07:20 PM ET (US) If you can top off the tank after each trip there is less room for water. The liquid gas will only expand so much as the empty area fills with gas vapor during the hot day and sucks in moist air at night.
contender	posted 05-23-2014 10:18 PM ET (US) If your cap is bad then yes, you could be getting water in from the cap, but I think you have another problem, its not like you hold the hose on your fuel cap when you are cleaning the boat, you are getting water from another place as well...
deepwater	posted 05-23-2014 11:48 PM ET (US) The tank, if on the deck for four days of heating and cooling along with fog or rain, could add lots of water to the tank. Topping off the tank reduces that.
RandyV	posted 05-25-2014 04:01 PM ET (US) I had the same tank in my Montauk. If your tank top is concave as mine was rather than flat like it is supposed to be so it would normally shed water, water will tend to sit where the tank hardware is mounted. If that seal is bad, you could get a huge amount of water in your tank. I was always concerned with that seal but stored my boat indoors and with it under the RPS during use. I made sure water was not puddling on the top of the tank. Empty the tank, spray that area with a garden hose then check to see if you have new water in the tank, or just replace the seal. The amount of water you are seeing in such a short amount of time can't be from normal condensation.
Ridge Runner	posted 05-25-2014 08:43 PM ET (US) The cap is "self venting" the original cap has been known to have problems and not last very long. My cap lasted only two seasons. Replace the cap. Kelch has a retail website BlueSkies - http://bluskies.us/fuelguages.aspx The replacement gauge is vented 2-3/4-inch threaded cap with a 12-1/4-inch float depth Kelch part number #7J203085 / BlueSkies part number #BK0130002; cost is $23.45. If you meant 50-percent of the tank is water - 12 gallons - that is a massive amount of water - and I can't believe that much water could get in the tank even if you had no cap on it at all/ If you meant 50-percent of the Sierra filter is water that very well could be the cap.
rjc1982	posted 05-25-2014 09:33 PM ET (US) I drained the tank, fuel lines, filter bowl and carburetor bowls. Replaced the the fuel cap, water separator and fuel filter. Motor started, ran for a few minutes then died. Acts like it wants to start but I can't get it running. Is there something else I need to do after having all that water in my fuel. It's a 2004 Mercury 90 Fourstroke.
contender	posted 05-25-2014 09:44 PM ET (US) Easy things to check are vent open and fuel bulb OK. I would try using 6-gallon remote tank, change the plugs, clean them, try a little starting spray. How is your fuel pump? Did you clean it out? Is your battery at a high charge (motor needs to turn over fast). Good luck
rjc1982	posted 05-25-2014 09:53 PM ET (US) Vent was open and primer bulb pumped up til hard. Did not drain or clean out the fuel pump. Will replace the plugs and see what happens. Thanks.
jimh	posted 05-26-2014 11:30 AM ET (US) According to the theory of magic water creation by diurnal temperature variation and condensation in fuel tanks, you should put your 12-gallon tank out in the sun for a few days and it would rapidly fill with pure water. I would keep this tank as a good source of fresh water. What if you were stuck offshore for a few days with a disabled engine--a very likely possibility in your case. This magic fuel tank that makes water all by itself could be, quite literally, a life saver. As you might infer, I am being sarcastic. Seriously, there is no way condensation from diurnal temperature variation is making 6-gallons of water in your on-deck fuel tank. The water is coming into the tank in only two ways: --the water comes in with the gasoline you are buying, or --the water comes in via a leak on the top surface of the tank A tank leak is not typically unidirectional, so if the water can get into the tank from outside, the gasoline could get out from inside. Turn the tank on its side and see if gasoline pours out from the cap or fuel pickup fitting.
deepwater	posted 05-28-2014 05:40 PM ET (US) A very hot tank with at half-full and subjected to a sudden downpour of cool rain could suck up a fair amount of water through the vented cap. amd repeated every day you might get several cups. The use of a tank would be ok. Fill with saltwater expose to sun and condense the vapors in a small cup.
rjc1982	posted 05-30-2014 01:40 PM ET (US) Do y'all see any concern or potential problem in trying to clean out my carbs by running the engine off a separate small tank with a gallon of fuel mixed with a full bottle of solvent like Quickleen or Seafoam?
jimh	posted 05-31-2014 09:51 AM ET (US) I do not recommend making up your own Witch's Brew of fuel and additives with concentrations in excess of those recommended by the engine maker. I prefer to use the fuel additives recommended by the engine maker and at the concentrations recommended for those additives.
rjc1982	posted 06-02-2014 03:32 PM ET (US) Hey All, I wanted to post a follow up on this issue with the results. I found 2 items that were allowing the water into my tank. One was the vent on the fuel cap, it was not sealing properly when closed. I'm sure that moisture from the air was getting into the tank there. The other was the o-rings around the fuel outlet fitting. I wash my boat thoroughly after each trip and that fitting was surely allowing a large amount of water enter the tank. After replacing both suspect items I drained and cleaned the tank, replaced my fuel separator,fuel filter and spark plugs then drained the carb fuel bowls. Motor fired right up and seems to be good to go now. Thanks for all the replies to my message.
deepwater	posted 06-03-2014 02:37 AM ET (US) That's nice to know
boatdryver	posted 06-03-2014 09:31 AM ET (US) rjc, thanks for taking the time to post the final diagnosis. doesn't happen always. JimL
contender	posted 06-03-2014 05:27 PM ET (US) Yeah its good to know the outcomes