Oops, Water in Gas

[Crabman]

I was readying the boat, 27' Contender with 250's, for a tilefish trip. At my age (71), I'm not making many of these trips anymore on the Contender and usually go with a friend on a 48' Ocean. My last trip was two years ago. With perfect weather, I wanted to run fast. I have four gas tanks. Three of which I rarely use. I didn't have much gas in those tanks and topped them off with 93 Octane to boost the few gallons in the tanks. I pulled a fuel line off one of my two saddle tanks and connected a inline electric fuel pump and pumped out a half gallon of gas. It looked perfect so I didn't bother doing the other side. We left 0500 and I decided to run off the saddle tanks first. I made it a half mile and my starboard engine quit. This was the side I didn't test. Limped home and pulled my water separator. It was full to the brim with water. Bummer, trip canceled. Later in the day I connected the fuel pump to that tank and proceeded to pull a gallon of water out. Why and how did that water get into that tank. I know all the places to look. Unfortunately, I don't fuel with my readers on. If I did, I might have seen that gas cap o-ring had micro cracks. I replaced the cap on the tank and put some water in the little well around the cap. Sure enough, in no time, it was gone and in the tank. So, for two years, rain and spray seeped into that tank. I decided to pull the boat out on my trailere and do a full gas system filter rebuild including the filter in the VST. I would pull the injectors if there was a problem after the rebuild. When done, I dropped in and took it for a test. Happy and relieved, the engine worked perfect. With that, I just wanted to put it out there how a $1.50 part could ruin your day. If you have the same gas cap, checkout the o-ring. It might save you a headache.

This type of gas cap's o-ring failed. Totally my fault for not inspecting it over the years. Also, I should have used these extra tanks during the year to make sure the gas was fresh.

 

[george]

There's always something, isn't there? When I was younger, stuff like that used to drive me crazy, and I'd scramble for a quick fix just to get back out there.

But over time, I've learned with boats the long way home is actually the quickest.

Well done figuring that one out.

 

[Crabman]

You have that right George. I'm very lucky to have a really good group of guys I fish with. While bummed I had to cancel after all the prep work, we all know we are on a boat and sometimes, although very rare on my boat, stuff happens and we roll with it. Like most guys, I try my best to keep my boat safe and in top condition but the bottom line, it's still a boat.

 

[Avenger]

Are you using ethanol-free gasoline? If you're not, you may have a bigger problem.

Ethanol acts like dry-gas and absorbs the water. Once it can't absorb it anymore it drops out of the mixture in what's known as phase separation. The problem with that is that ethanol has a very high octane rating and they use it to boost the rating of low-octane gasoline.

I see you used 93, but I wonder about the rating of what is left.

 

[Crabman]

Thanks for your reply Avenger. I understand the whole ethanol situation. For me, the leftover gas and ethanol was not my problem. I only had about five gallons in the thirty-five gallon tank. I know there's a back and forth about how much fuel to leave in a tank over winter but this is the way I do it and for me, it worked in the past. Each year, I fill with 93 to make sure the bit of gas leftover was mixed with fresh gas that will boost the octane of the stale gas. I feel octane loss and stale gas is a bigger problem than the phase separation on an engine that likes 89 and above. I also know, octane above 89 will not give me more horsepower. The leftover gas was not my problem. One problem was not using that tank last year but, It was the leaking o-ring that allowed a gallon of water to seep into the tank. My other two idle tanks had no water after sitting just like the tank with water. So, basically it came down to a few things. One: was there a leak on top of the tank allowing water to enter the tank. Answer to that, no, I would have gas in the bilge after topping the tanks off. Two: a fill hose has a leak allowing water into the tank. Big stretch but again, no. On my boat it would be very difficult to get water into a fill hose without seeing some gas in the bilge when the tank is being filled. Three: the gas cap. Only one tank had water and it was the only tank with a cracked o-ring. There are other situations that could cause a problem but I will wait and keep an eye on my water separators. Time will tell but I'm totally comfortable with the o-ring being the problem. I put this out there in hopes others might check their o-rings and not have the problem I had.