petrol filter problems 2005 150 hp

Ive got a mercury 150 optimax 2005 and ive got a problem with water getting into my petrol tank I was told to drain off the tank and start again,so I drained 78 gallons into clear containers with no sign of water in it.so it all went back in.changed the filter and went fishing, after a bit of running, off went the beeper four times to tell me the problem was back.I had to remove the filter and clean it out five miles offshore which was quite tricky hanging over the stern.now what I want to know is can I put another fuel filter inline fixed into the boat well before it gets to the engine so i can monitor it and empty easier.I must also add I cannot get to the 120 gallon tank as it is sealed below deck could it be condensation? very grateful for any advive

Re: petrol filter problems

Do not know where your tank vent / overflow fitting is.--------Have a look at it, you may be taking in water there from waves or spray.

Re: petrol filter problems

thanks racerone its a good idea and something to iliminate next time I am out its a 7 metre boat and the tank vent is about half way along but quite high out the water and not very big but water would get up around it when we are travelling so its something to look at. many thanks

Re: petrol filter problems

Yes you can put in a second filter.
It's called a fuel/water sep filter.Get one with a sediment bowl that way you can see what's going on and head off any problems.
I had a tank that kept getting water in it and couldn't figure it out.
Seems Ethanol had weakend it and it would let gas in the system through a weak spot in the hose.J

thanks Jerryjerryo5 I am planning to go down to the boat after the christmas break and fit another filter as you suggested.I will keep you imformed of the outcome