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Water in fuel tank, 25 ft. Sportcraft-I/O

5K views 34 replies 16 participants last post by  ress 
#1 ·
Looking for advice. 1984 Sportcraft, 228 mercruiser. Boat stopped dead in the water after running fine. Water separator had quite a bit of water in it. Changed separator and carb filter, got boat running again. This happened twice. I drained the entire tank and cleaned out what I could. Filled it around half full with gas, (From the gas station, I assume E10 ethanol.) Boat ran fine for about an hour, sat for 5 days. They took it out yesterday and it failed again. Same issue, separator full of water. Any ideas would be appreciated.
 
#2 ·
Saw this happen on a buddy's boat. Water was getting in thru the breather cap for the gas tank on the side of the boat. The cap was turned forward and spray was going thru it when he ran - especially in rougher water. Check your breather cap. Too much water to have gotten it from the gas station. My buddy had 2 different marine shops drain his tanks when this happened. One installed a separator which the water overwhelmed next time out. Both shops said bad gas. On the third time, we took a closer look and finally figured out what was happening. There is only a couple of ways water could get into you tank.
 
#4 ·
Someone else mentioned the vent on the tank was the problem with theirs. I think my vent is on the stern with a clamshell pointed down. My gas cap is solid plastic, no venting on it. I agree there is only a few ways to get water in there. I am going to check the vent out and see if there is another one I am missing. Thanks.
 
#3 ·
I told those kids that was not a PEE HOLE.LOL , bad thing , I agree only two ways into the tank, fill and breather pipe. on a older boat yrs back I pulled the sending unit out and sucked all the fuel out. that fixed mine , and use a grade better fuel. and a can of sea foam ,or berrymens in each tank, your engine will like like it. theres a third way condensaon
 
#7 ·
If you have a metal tank it could be corroded on the top side. When it rains it'll take on the rain water.
I've seen this happen on a friends sportcraft. Just a thought you might want to consider.
 
#9 ·
I had a lot of water in my twin tanks. Won't admit how it got in there! Anyway, I had a fuel polishing service out of Marblehead come out to my dock and filter the fuel. It was quite a process as he said my tanks had several baffles in them to keep the fuel from "sloshing around" and the water was trapped behind these baffles so he had to thread the filter tube behind each baffle and then repeat the process several times. It worked, I never had more than a thimble full of water in my seperators after he filtered it.
 
#15 ·
The process used was challenging to thread the small semi rigid plastic suction tube through the tank baffles to get to the lowest point in the tank. Due to the amount of water it required 3 suctions before he was satisfied that he had sucked out the water trapped behind the baffles. Keep in mind too that he uses very good filtration equipment. Yea, it was expensive but the last thing I wanted was to continually battle engine shutdown due to clogged water/fuel separators. I've had no problems.
 
#20 ·

This is the specs from Startron
Features

  • Cures and prevents most ethanol problems
  • Makes all engines start easily, run smoothly; improves performance
  • Removes and prevents gum, carbon and varnish
  • Works in all engines and in all fuel
  • Helps prevent phase separation by dispersing water throughout fuel as submicron-sized droplets that are safely eliminated while the engine operates
  • Improves performance and fuel economy.
  • Stabilizes fuel; helps rejuvenate old fuel
  • 1 fl. oz. treats 16 gallons of fuel
  • Reduces smoke and all other emissions
  • Keeps fuel delivery system clean
 
#25 ·
This is the specs from Startron
Features

  • Cures and prevents most ethanol problems
  • Makes all engines start easily, run smoothly; improves performance
  • Removes and prevents gum, carbon and varnish
  • Works in all engines and in all fuel
  • Helps prevent phase separation by dispersing water throughout fuel as submicron-sized droplets that are safely eliminated while the engine operates
  • Improves performance and fuel economy.
  • Stabilizes fuel; helps rejuvenate old fuel
  • 1 fl. oz. treats 16 gallons of fuel
  • Reduces smoke and all other emissions
  • Keeps fuel delivery system clean
This will not solve his problem.
 
#22 ·
Check all entry points mentioned. O ring on fill cap. Vent allowing water entry, even tank corrosion. it is getting in there somehow.
The best way to remove water from your tank is if there is a drain on the bottom of the tank. Since this is not likely you should have access into the tank to drop a suction point to the bottom of the tank. Pump out until the liquid is clear. Wait 5 or 10 minutes and pump some more to see if still clear. To be completely positive remove all liquid from the tank. This could be a challenge if you have a large quantity of fuel since you need to put it in containers and remove for use elsewhere or for disposal if it is cloudy. Fill with the usual grade of fuel you use. Be sure to now clear your fuel lines and install new filters / separators.
If problem occurs again the water is getting in the tank from one of the areas mentioned by others.
 
#28 ·
The ONLY way condensation happens in a fuel tank is if the water is already IN it....gasoline does not consensate...other than what previous post have mentioned i have no clue what your problem is....but its not condensation that magically got into the tank...
 
#29 ·
Oh by the way.. the vent system on your sport has an in-line ball check in it, will evac pressure and vent outward but will not let anything come in from the seaside.
That pretty well narrows it down to bad O rings on the filler cap or a corroded gas tank - please post what you find just for future info.....one other possibility that hasn't been mentioned is that someone vandalized your boat.
 
#30 ·
The ONLY way condensation happens in a fuel tank is if the water is already IN it....gasoline does not consensate...other than what previous post have mentioned i have no clue what your problem is....but its not condensation that magically got into the tank...
Any fuel tank with a vent is subject to condensation...

This problem is not condensation.
 
#32 ·
Let me tell a little story.. I had twin aluminum tanks. Ethenol and aluminum are two sources for water. I had a lab give me the results. It's been 10 years ago but I got to be some of the first reports of this problem. I had rebuilt my boat. One thought was when I put the new vent hoses on I didn't make sure they were tilted up in order to keep water from running down into the tank. The water in the gas was crystal clear. I had they tanks purged a couple times before we figured out about aluminum excellerates the break down of Ethenol in the gas. There were some good articles written in some of the popular boating magazines. Try Google to find out more.
 
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