water in fuel

I own a 2005 1850 Crestliner Sportfish with a 2006 150 Mercury OptiMax and I am currently having issues with water in the fuel. This has been happening for a couple years. The first time I took it to the dealer and had them drain the fuel tank. Then this past year I have just drained the fuel myself to save money. I am wondering if anyone else has had this issue and if so how did you fix the problem. Thinking it maybe could be the fuel cap? We got 3 inches of rain last night and today when we took the boat out the alarms went off and there was water in the fuel filter. Help! I am getting very frustrated with my Crestliner.

Do you have fuel/water seperator before engine filter?

Also, if only using your boat few times a year I’d recommend using non-oxy gas.

Maybe seal on gas cap is gone?

Make sure your vent line is clear. I plugged my vents with polish on the screens. It created a suction that pulled in rain or spray past the cap. If you can’t blow thru it,…its a problem.

i just looked at an 1850 a friend has to see where it can be coming from and everything is covered except the fuel cap I think its your problem. its not that hard to replace would do that asap and like everyone is saying put a fuel seperator in line. the vents are under the gunnel but it is possible that they can be the culperit but you said that the problem didnt ocurr until after the rain. I wouldnt take it back to that dealer you woould think they would help solve the problem so that you dont have a problem again

I always run a fuel/water separator.also on my built in tank
on my jon boat I cut a plastic bottle and put it over the fill cap ,cured my water problems
kp

Just had this issue on my 115 opti! After taking the cowl off of the motor (left side I think when looking from the back) there is a fuel module about the size of a note book. There will be a red castle looking circle. That is the fuel filter. Directly below that there will be a black hose running in a u shape from left to right. Dissconnect it from the right side and put in a clear jar or beer bottle. It should simply slide off. Then look above where the hose connects about a half inch, there will be a little brass screw facing forward. Looks like a carb screw, loosen it a few turns, then grab a rather large screw driver and use it across the fuel filter (red castle) until the vacuum is released and fuel/water runs out the hose. You might need to loosen the little screw more until water starts running out, then let run until empty. You will see the seperation in the clear jar/bottle. Fuel floats on water so the water will come out first. Replace fuel filter with a new one, tighten screw and reattach hose. Done.

There is a sensor in the port below the filter that senses water once a decent amount of water settles in there.

Pm me your number if you have questions and I can walk you through it over the phone if you want. Its easier than it sounds.

Paulh he can do that get him up and running but that doesnt solve the problem have to get to the source so it doesnt happen again. One thing he can do is and its a pain is take the hose off the filler cap then put a rag down the tube so no water gets in then put water on the cap to see if that is leaking do the same with the vent lines the lines are not easy to get off so get a hose tool looks like a screwdriver bent and sharpened to go aroun the inside of the hose to get those buggers off

It would really help to be able to quantify how much water is getting in. Theis can, of course, only be known by draining the whole tank and running everything through a seperator.

Obviously, the lead suspect is the fuel cap and the vent. From the OP, I’d like to know:

1. Where is the boat stored. Iniside, outside?

2. Is it covered in such a way that most if not all of any rain will run off and not get to the fuel cap or is it uncovered?

Personally, I’d be tempted to replace the fuel cap and rig up some way to cover both the fuel cap and the vent to protect them from rain and see if that fixes the problem.

I’d also install a Racor filter / seperator unit. These are the best of the best, it’s what the big boys use and for good reason.

Grouse

Also it is probably a good idea to store the boat with the tanks full. It leaves less room for condensation to form on the inside of the tank during those temperature changes.

Mercury does not recommend installing another fuel water separator on the Optimax`s, since there is an onboard one under the engine cowl. Mercury claims it can cause a lean condition and everybody knows what that means….KABOOOOOM.

Thanks for all the advice. I believe the problem is the fuel cap/vent and I am going to try and replace that. Thanks again.