Need to find source of constant water-in-gas

[BMarkey]

I finally got my fuel starvation issue solved (I think), after rebuilding the Johnson year 2000 115 VRO pump, tightening the fuel hose clamps and adding a new primer bulb (probably the problem the whole time).

But now my original problem (started last year) is back - water in the gas. It ruined the Fourth of July. The engine ran great, but as the bow rose sharply as I hit the throttle hard, I assume the water build-up went to the lower rear of the gas tank and right up the pick-up tube. The Wellcraft 190 Fisherman was dead in the water.

So, I really need to identify the source of water and need your help. Last year, I assumed the water was leaking through a deck plate right above the gas tank behind my captain's chairs. The top of the plastic tank is sunken in a bit where the sending unit is screwed in and I assumed water was pooling on top of the tank and leaking into the tank through the old unit. I replaced the unit, better sealed the deck plate with 5200 and left an old rag wrapped around the new sending unit to check for water.

It's a closed transom boat, so water will build up on the deck briefly as it rains and I wash the boat. Two drains in the rear corners allow the water to flow out via through-hulls. I assume water also gets under the deck from the live well area, anchor locker and the storage compartments under the front casting platform and bow area.

Possible sources of the water:

Deck plate, still? - The rag I left under there on top of the tank is dry. That should indicate the top of the tank is no longer the problem, right?

Gas cap? - It's old, a self-venting model that sits on the side of the rear. Water cannot build up around the cap and the cap is tightly screwed on but its O-ring is old and brittle. But could this result in a half-gallon or more of water intrusion? BTW, I can't find a replacement (stainless type) round cap.

Tank - Could water, below deck, be entering the gas tank through a crack? I would tend to doubt that because gas does not leak out and I do not smell a gas leak. But if the crack is near the front of the glassed in tank and I rarely fill the tank, maybe water can get in without gas leaking out?

Fuel hoses soaking in water inside the transom? - That doesn't seem likely because the water seems to be in the tank.

The tank was almost dry yesterday and the engine ran well. I added 10-11 gallons of "cheap" E-10 just before launching.

That's it. I hope some of you can enlighten me as to how to solve this excruciatingly frustrating problem. Thanks.

[BIGDAWG2566]

CHECK WHERE THE FUEL TANK VENT IS

[BMarkey]

I have a self-venting cap system.

http://www.iboats.com/mall/image/view/2/3/2820540c_1.gif

The smaller tube is apparently the vent. It has a hose going into the tank. I don't see how a gallon or more of water could quickly get in through the cap.

[Sans Peur]

Have you pissed off any neighbors lately?

I would add a Racor Filter to the boat. When the glass bowl fills up drain it and keep going.

[BMarkey]

I thought about the possibility of a neighbor dumping water into the tank, but I do not think she or he could get over the fence and my dogs woud go crazy if she did. I do have a next door neighbor (renter) who sits on her porch just a few feet from where I park the boat. The village forces me to park it there because I am not allowed to put it in the rear yard (only the side of the house).

[goodride]

does the water get in when the boat sits? the first responder mentioned the fuel vent..we have put a perko stainless clamshell over the vent facing down and back if your vent sticks out we made starboard horshoe shaped spacer to clear the vent.

at pep boys or any auto store you can get an electric fuel pump for abot 30$

my boat had the same problem as yours..

. i attatched the hose tie wrapped to a piece of the small section of copper tube..not sucking thru the tube but bending the tube to hit the corners of the tank to get ALL the water and went thru the gas gauge hole to the rear corner of the tank having the bow up.. I figured the water would go to the lowest point.

for now it seems ok!!

[BMarkey]

I have no vent. The boat has a self-venting fuel fill.

I have some copper tubing that I attached to a plastic hose and the primer bulb last time. Getting the last of the liquid out was a real chore because of having to hold the copper steady in one spot while pumping the bulb.