Merc 90 tower of power water in fuel

[katch_me]

So have been dealing with a problem for awhile and I’m trying to get down to the root cause. Maybe I am missing something so that is why I’m asking here. Every weekend when I go and try and start it won’t. I have narrowed it down to fuel. And water in fuel. To start it I hook a portable tank. It starts. I run it for a bit then I hook up my below floor tank again and it runs fine all weekend. Until it sits for a bit. That’s when I think the water settles to the bottom.

so the obvious is a leak somewhere. But I can’t find it. It looks good! No fuel is leaking out. At one point the bilge flooded and I believe at lot of water got in at that point and I did notice some loose screws on the fuel gauge connection. I think that is where water got in. I sucked out what I could but still some is on there. Maybe this is just the residue of the water and eventually it will be gone? I just added some “water remover” additive. It’s probably ethanol. I’ll see if that works. At this points it’s got to be very little water in the tank. It just seems like my initial start would be drawing water and maybe hitting the spark plugs.
My question is more on the lines on condensation. It seems like the tank vent is open to atmosphere. Is that how it should be? Or should there be some vapour pressure in the tank? Thanks for your comments!

 

[Chris1956]

Condensation is not your issue. There is very little condensation and the alcohol present in regular unleaded gasoline will easily absorb it.

The real fix is to lift the tongue of the trailer and pull the fuel gauge sender off the tank. Now stick a siphon hose into the bottom rear of the tank and suck out as much fuel as possible into Jerry cans.

Now let the fuel set for a few minutes and siphon from bottom of jerry can to clear container. Now you should see any water. A dash of 2 cycle oil will make the water really visible.

Pour off the good fuel and reuse. ditch the water.

Permetex makes a fuel proof gasket dressing. I recommend you coat the sender unit gasket with it and reinstall with all screws.

 

[katch_me]

Condensation is not your issue. There is very little condensation and the alcohol present in regular unleaded gasoline will easily absorb it.

The real fix is to lift the tongue of the trailer and pull the fuel gauge sender off the tank. Now stick a siphon hose into the bottom rear of the tank and suck out as much fuel as possible into Jerry cans.

Now let the fuel set for a few minutes and siphon from bottom of jerry can to clear container. Now you should see any water. A dash of 2 cycle oil will make the water really visible.

Pour off the good fuel and reuse. ditch the water.

Permetex makes a fuel proof gasket dressing. I recommend you coat the sender unit gasket with it and reinstall with all screws.

Thanks. I have done exactly what you said earlier. However I know I didn’t get all the water out. I could get the last little bit through the fuel sending unit. I am hoping that my problem now is just that last little bit of water. Time will tell as I was only able to test once since I drained the water.
I use fuel without ethanol so it won’t absorb the water.
Next time I let the boat sit for a week or two I will disconnect the fuel line and pump some gas out into a clear jar. See what I am dealing with.
I did notice that my fuel cap gasket is hard. Although I can’t really see how water can get in. I will change regardless.