Its true.... condensation happens

SeaHare

The weather here in Wisconsin has been cool and windy for the better part of 6 weeks now and we havent been on the boat for a month. Yesterday I stopped by the boat just to fire up the engines and genny to let run up to temp and stretch their legs a little. 

I fired up the port motor and genny and all was well, ran about 20 mins or so. Then I fired the SB motor and it began stumbling and died after about 5 mins. I checked the fuel/water seperater and it was full of water. So, i ran to the store and picked up a few new separators, prefilled one with gas and installed it on the SB motor.

The motor Fired up and ran great, i started buttoning things up thinking its all good when the motor died again and would not start. (ran good off the gas i prefilled in the filter) I checked the separator and again, it was full of water.

So, long story short, i removed the metal gas line from the carb and hose clamped a clear tube about 3 feet long to it and pumped out about 4 gals of gas/water mixture before just pure gas started coming. I took a few samples afterwards and its definitely water free. I figure about 1/2 gal of water was removed. I then replaced Filter/separator, and all is well again.

Lesson learned, the boat only had about 1/8 of a tank left. I cant let it get that low again. I figured the season was close to being over and didnt feel like filling. After owning boats for over 15 years, ive never had this happen. I though i was immune

Handymans342

Did the gas you used have ethanol?

SeaHare

No, no ethanol

Dream_Inn

Interesting for sure!  I guess it brings that winterization subject back up each year.  I've always made sure my tanks were ~ 95% full with stabilizer.  I've also been adding startron in it all the time.

Michael T

@SeaHare. I really doubt that water came from your gas. IMO that volume doesn't make sense. I'd be looking for a loose fitting somewhere that let rain into your tank(s). I too have never seen non-ethanol gas behave that way unless some other extreme factor was at play. I suspect some sort of leak letting water in. THAT I have seen plenty of.

randy56

Once I had rain water getting into gas cap, Bad o ring, so much had to drain out half tank and start over with new gas.

Michael T

@randy56 - exactly, have seen that one a dozen times plus water getting into fuel lines and vent lines and down vent cowlings.

MDboater

I think that you should consider sources of water other than condensation.  My math might be off but I calculated 9.5 ounces of water from condensation using the following assumptions.  

Max temp during the day:  79 F
Relative humidity: 100%
Empty volume of tank: 100 gallons
All water condensed from the air into the tank each day
1 cooling cycle each day
30 days

BellevilleMXZ

Yeah the o-ring was missing off my cap when I bought it....fixed that quick, looks like rainwater would run right in

Michael T

@MDboater. usually, if the boat is in the water, temperature swings are highly mitigated. If on land it shouldn't happen because IMO the owner should have only non-ethanol in the tank(s) or highly treated ethanol to avoid extreme phase separation. All of the discussion aside (I haven't seen everything, yet) but I have never seen that degree of water present - in those circumstances - without a leak being a culprit.

SeaHare

I really want it to be condensation, but i accept the fact that the water could have come from anywhere. Over the last 6 weeks we have had some pretty extreme weather here. Hot, cold, windy, stormy... Ill be keeping a close eye on it to see if it continues and also give it a once over to see if i can find a source.

I just hope the tank isnt compromised...that would suck!!  Not even gonna consider that yet..

Michael T

I doubt it is your tank. I think it more likely to be getting in somewhere that is cheap and easy to fix.

MDboater

Completely agree MT.  The water condensation, or how much water condenses out of the air in the tank and into the gasoline is proportional to the temperature swing.  So a lower temperature swing would correspond to less water condensing into the gasoline.  

I wasn't explicit on this point but I didn't make my assumptions to show the likely ambient conditions.  Rather, I used these values as extreme worst cases to show that 1/2 gallon of water in the gas tank could not be explained by condensation during a 30 day period.