Water Getting into Fuel Tank

[ttgoddard]

Hi,

I have a 2017 Bennington 21SSRX with 115hp Yamaha. Before I put it in the water this season, I took it to my local gas station and filled it up (maybe a half tank, it was already half full) with non-ethanol high octane fuel.

As soon as I had it in the water, it ran terribly, typical sign of water in the fuel. I tried fuel dry to no avail. Then rigged up a six gallon fuel tank and it ran fine on the fresh tank full of fresh gas.

I pumped out all 24 or so gallons of bad fuel as best I could, put in another couple of gallons, rocked the boat and sucked that out too. I hooked an electric fuel pump up to the fuel line right before the primer bulb.

I put fresh gas in along with three cans of SeaFoam to dry up any moisture or water that might have been left in the tank that I could not reach.

All was good for a while, but now it is just as bad as ever. I keep pulling off the water separator and it is full of water after even a short run.

I don't see any gas leaking in the water, but it appears I am getting water into the fuel tank, any ideas?

If I pull it out of the water, is there a drain plug where I can make sure I get every drop of water/fuel out?

When I run at about 2,200rpm so it's not planing, it runs well as if the water in the fuel tank is at the rear bottom of the fuel tank away from the pickup, as soon as I slow down, it starts picking up the what I assume is water again and runs real rough, will hardly idle.

I know water attracts water, could it be condensation accumulating, we're in upstate NY so we have been getting some hot days but also cold nights too.

Ideally, I'd like to know if there's a drain plug so I can get every drop of fuel out and start again, or if anyone else has had an issue with water getting into the tank somehow.

Thanks.

 

[kaydano]

Doubt there's a drain plug.

My guess is water spray from under your boat is being forced into the tank somehow when you are running.

There is a breather charcoal canister for vapor emissions from the fuel tank. My 24SSL has a hose that hangs down between the center toon and one of the outer toons, but angles towards the back of the boat so water isn't forced into it. Could be yours is positioned pointing forward such that water is being forced into it. Or water is being forced into something related to that vapor filtering system.

Check that out.

If water definitely got in there when you were NOT running the boat, then it's getting in some other way. But it would take a lot of rain to fill a tank.

 

[kaydano]

If you have a motor pod tank, there should also be an access cap for the fuel sender in the floor of your boat somewhere over the fuel tank. Unscrew that. It's 6 to 8 inches in diameter, and plastic. It has indents where you can put your fingers and unscrew it. Once you get that off, check and see if any of the fuel sender connections are loose such that water could get in. That should be the only other hole in the tank other than where the gas goes in. You could check that filler hose connection too, but guessing if that was loose, gas would come out when filling it.

Good luck!

 

[the-little-B]

I had a problem gaining water also. My fuel tanks vent to atmosphere was drilled right on top of a cross member and the water was forced up to the vent while underway.

My tank is located inside my livewell in the back and fairly easy to get to. But you’re going to have to trace some lines and see what’s what.