Aquasport 175 - Water in Tank

[pjorzekop]

I have owned the boat for 3 years now, first couple years it ran totally fine. at the end of last season and about 3 weeks into using the boat this season, I am finding water in my tank. At the end of last year we had pumped out as much of the gas as we could and started fresh this year. I replaced the water separator on my boat this year and just the past week i have noticed water being collected in it. I would drain it, it would fill up clean and then as I would be out motoring I would notice more water getting into the separator. So I basically drain it every time I go out and every time I come in. Can't figure out how it might be getting in. I have no gas in my bilge when I pump out, there is no smell of gas nor do i see a slick. Could it be the vent on the tank sucking in water from my bilge? I am not even sure where the vent might be? I also have a perko fill tank and there is also the vent in this and I have read issues of them not being sealed properly? Could water get in that way? Is it possible there might be holes on the top of my tank water is getting into?

I replaced the sending unit my first year as it was loose and at that time I noticed fuel in my bilge. I brought it to a mechanic and he said it was totally loose and then the gas splashed out from going over wakes. I also don't notice any water collecting ontop of the sending unit, it is bone dry after I wash it.

Any help or advice would be greatly appreciated....

[Capt. Bob]

Interesting problem but at first glance, you seem to have reduced at least several areas of concern.

If you don't see or smell fuel in the bilge (or tank coffin?) it would appear your tank is sound but....
What year is your 175?

I don't believe it's SOP to vent the tank to the bilge so that should eliminate that idea but....
We have seen water enter through the vent tube located on the outside of the gunnel below the fuel fill. Still, unless its orientation has been recently altered, it probably isn't the source. 

This leaves the easiest way for water to enter a properly sealed and functioning tank, that's through its fill source. Have you been filling up at a different station/marina? Possibly got some fuel just prior to the station filling their tank that had been contaminated? This was the norm years ago at an aging marina we filled up at in the Keys. Lots of water, on a regular basis. This was pre-ethanol days.

Good luck.

[pjorzekop]

Thanks Bob its a 2000, I usually fill up at a local gas station so its possible maybe I got some bad gas from them that had water in the tank? Like I said its not a lot, but it was enough to originally make the engine skip a little which was when I realized I had water in the gas. It must have been bypassing the separator because that had been filled. I did notice on the top of the perko gas cap there are 4 little slits which might be how it vents out. Its possible water is getting in thru this when it rains or when i wash the boat. I am going to open up the hatch this weekend to see if there is something wrong with the tubing.

[Capt. Bob]

Great idea. Post a few pics of what's going on down there.

Thanks and good luck.

[Brendanpd28]

Note really clear on how your tank vent is setup but that was the source of my issues.  I had A LOT of water getting into my tank....theres a thread somewhere on here about it. Mine is on the outside of the gunnel below the fill like Bob was describing.  I had to put a large clam shell over it to prevent wave water from splashing in.   

[pjorzekop]

my vent is built into the fill like in this picture, its the smaller tube

[RickK]

I have the same fill as you show - do you have a vent tube attached to the little tube and connected to the tank?
You can also try to sort out what is going on - whether it's water from the station or what by using one of these when you fill up
http://www.mrfunnel.com/Mr._Funnel/Home.html

[pjorzekop]

yes the vent tube is attached to the little tube, i made sure of it tonight.

[mshugg]

You don’t smell fuel in the bilge.  That would seem to eliminate the following:

Loose sender
Pin holes in the tank
Loose fill or vent hose below deck

Process of elimination, water is in the fuel when you buy it, a product of condensation or leaking fuel fill.  These are simple systems. 

Condensation-Are you keeping the tank full?  Or letting it get empty.  This one is controversial, but some report it can be a source of water.

Bad fuel-the funnel Rick suggests would eliminate this.

The fuel fill-parts do get old, and since you mention changing the O ring, this seems to be one thing that has changed from no problem to problem.  It seems to me, the simplest solution is to change out the fuel fill.  Spray, wash down, if the fill isn’t sealing, this would seem to be the most obvious source of water.

[pjorzekop]

Today I pulled out about 16 oz of water. A lot more than I did the other day. Seems to be more
In it s well. We haven’t had any rain and I haven’t washed or added fuel to it. I just find it hard to believe air cold get in they the fuel fill. Almost seems like way too much water. I’m confused beyond belief about this.