Water entering fuel tank vent 17hpx

[RCH91]

Hey guys,

I bought a 2004 17 hpx about a year ago. The boat was great until I ran it to a single bar of gas and began having engine trouble consistent with a fouled carburetor. Long story short, the mechanic told me that salt water was entering the tank (salt crystals in carbs). So I had the carbs rebuilt and the tank drained and the boat runs perfect and still does. Problem is that I changed the water separator a couple weeks back and found that there was a decent amount of water in it, especially for starting from a clean tank 4 months earlier. I pumped the tank again myself and found about a pint and a half of water in it (unable to verify if fresh or salt).

So now the question is how is it getting in? After the first incident I replaced the fill cap (with exact same cap) and tested the fill neck for leaks. I'm confident that is not the issue. I've made sure the fuel sending unit is properly sealed and so little, if any, water drips on the tank anyway I doubt that it is entering through there. The tank itself shows no sign of corrosion and there is no scent of fuel in the hatch so I'm doubtful the tank has a leak. The boat is covered between use and is not exposed to rainfall.

So this leaves the (likely) option that over the course of a windy spring, water has been entering through the fuel tank vent. Before I start changing things around or adding clam shells I wanted to see if anyone has had a similar issue. I called the factory a while ago and the really nice guy I spoke with said he wasn’t aware of a single instance of this.

The vent itself is a stainless steel flush mount style. The vent is located so close to the deck cap that it is not possible to create an upward loop in the line between the vent and tank. Also, due to this there is barely any uphill slope in the vent line before it turns back towards the tank. This has always been a concern of mine, but I tend to trust MBC has got it right… It is possible a previous owner altered something (I'm the third owner and the guy I bought it from said he didn't change anything and also said he hadn't experienced the water issue).

Has anyone had a similar experience?

Can anyone with a 2004 17 hpx provide a comparison to the way their vent/vent line is set up?

Am I missing another entry point for the water?

Thanks for taking the time to read, I appreciate the help.

[Coto]

Where do you fuel up? The gas station you use might have some issue with water in the tank.

Once I remember my buddy’s skiff to a crap one weekend cause we fueled at the Flamingo gas pumps and as a result had water in the tank. That was years ago but I know some guys had issue with the gas station in Everglades City with water from their tank after fill up. 

It sounds like you’ve got everything squared away, the gas station is my only guess. Maybe someone else has a better idea. Good luck.

[RCH91]

I usually fill up at a Wawa in Fort Lauderdale or Mobile (I think) in Florida City. I had that thought, but the first time around it was salt water in the tank and I kind of doubt salt water is getting in at the gas station. Thanks for the response.

 

[hawg]

Given the low gunnels on these boats and the conditions that we operate them in, I can see where it is possible that some water could make it into the fuel tank through the vent hose. I think it is just as likely that the water comes from the bottom of the tanks at the service stations or from the tendency of ethanol infused gasoline to attract water from the atmosphere. Also be aware that if your transducer is producing a lot of spray,  that spray WILL be ingested into your carburetors. Although this would not account for salt crystals in the carburetor bowls, it will leave salt crystals in the intake passages. I rigged my 17 HPXV with a Racor filter with a clear bowl that can easily be viewed and drained. I've been able to prevent problems by inspecting the bowl before and after each trip to see if I'm getting any water in the fuel and draining it away before it gets into the engine.