Water in tank

[romair]

Left KGYY this morning. I always prefly thoroughly especially since the airplane sat on the ramp for a few days and it has been raining in Chicago. First time to find water in a tank...got about 5 draining containers worth of it. Made me quite nervous, especially since the fuel truck had just finished fueling the other tank, so I did not know if there was water in that tank as well. I waited for about 15 minutes and sumped it, but no water. Regardless, I switched tanks only when I reached my 8k cruising altitude....

[Marauder]

Yikes! Do you have bladders or original tanks?

Sent from my iPad using Tapatalk

[romair]

Tanks were resealed about 4 months ago at weep no more. I suspect it is the fuel cap, although Paul replaced the o rings. It is significantly harder to push down the tab on the other fuel cap once it is switched to the closed position as compared to the side where I found water in.

[BKlott]

Not knowing the history of your airplane or how long you've owned it, let me share an experience that I had with my Grumman Cheetah shortly after I purchased it many years ago. Started getting some water from my right tank during pre-flights. Not a lot but some. Looked in the tank and saw what looked like a clear bubble in the bottom of the tank. Tried draining some more but was just getting Avgas. Here is what happened.

Some BOZO had replaced the fuel tank drain with an incorrect drain unit that had a pickup higher up than the correct unit. This allowed a section of water and sediment to remain in the bottom of the tank, below the pickup hole in the drain. Of course, their were no log book entries about any changes to the quick drains.

This may be something to consider looking into. Does your airplane have the correct quick drains?

[romair]

Yeah, definitely the correct quick drains.

[DrBill]

Looks like same amount of water I got in my Beech with old O rings after a rain storm.

BILL

[M20F]

I changed my O-Rings after similar situation and problem resolved. Could be they were installed incorrectly or the new ones were just bad. Cheap fix and would be first thing I try.

[Piloto]

An overlooked source of water leak is the filler hole adapter ring. Sometimes they get rusted through and leak water. With age the sealant on the adapter ring deteriorates causing it to leak. It will not show a fuel leak since it is at the very top of the tank. To check for leaks on the adapter ring simply blow air by mouth into the tank vent and check for soap bubbles around the ring. Replace the ring if rusted or reseal the perimeter.

José

[DAVIDWH]

My water, and a significant amount, came a day after a wash and wax.

 

Replaced  O-rings and future problems solved.

 

Read on another blog that it takes about 5-6 hours for water to filter down to the drains after refuel.

 

Thus, draining tanks immediatly after refuel is an exercise in futility.

 

Are those numbers correct ??

[The-sky-captain]

I've heard 10-15 minutes...

[Hank]

I've also heard 10-15 minutes.

 

While the oring around the outside of the cap is easy to check and replace, there's another little one on the inside, too. The cap must be partially disassembled to see it. This oring is often overlooked, but it should also be changed.

 

Sounds like your caps are leaking.

 

As for being hard to close, put a drop of lubricant on the shaft at the top and let it work its way down. I use TriFlow for this; at my last annual, they quirted white lithium grease on it before I knew it. But it works much easier!

[MyNameIsNobody]

Line guys (when they fuel plane) about 50% of the time cock the caps. They are not flush. They are really difficult to open when this is done. Screwdriver needed to lift locking tab. The fuel cap is not getting the proper seal when cocked....

My center (at top of cap) will be full of water with a heavy rain. You need to carefully remove or water will get in tank upon removal....Not much, but a little.

[Mooney20]

That is WAY too much water. The easiest and best way to end up with that much in a tank that has a properly maintained fuel cap is to install the cap cockeyed as mentioned above. It's all too easy to do and line personnel did it to mine regularly. A properly installed cap will be flush and even with wing skin. An improperly installed cap will be cocked ever so slightly higher on one side. When you know what to look for, it can be spotted immediately.

[M20F]

I _always_ babysit fueling and _always_ remove/reinstall my own fuel caps for precisely the "cockeyed" reason.  It's easy to get right, but easy to get wrong if you don't know the feel.

I would add I fill mine because they like to use the nozzle to bend the metal ring just inside the tank as well.

[M20JFlyer]

This comment is not water related but is fuel being added comment

The mooney owners with the sight tank gauges

Observe the number of " line people " who point the fuel filling NOZZLE toward the fuselage ... HENCE pumping a strong stream of fuel directly at your sight gauge .

CAN ANYONE on MS share ... does our POH mention avoiding a forceful stream of fuel at the sight gauges mechanism ... should be avoided??

I have had to correct or instruct fuel people multiple times ..not to point the fill nozzle at the sight gauges.

[jetdriven]

I _always_ babysit fueling and _always_ remove/reinstall my own fuel caps for precisely the "cockeyed" reason.  It's easy to get right, but easy to get wrong if you don't know the feel.

In my experience I've seen line guys attempt to bash the fuel cap tab down with the heel of their hand because the cap is cocked. One guy in FXE couldn't get it with his hand so he started to use his flashlight. Anymore it's like towing. Absolutely not unless I'm present.

[cliffy]

It can take 5 or 6 hours for suspended water to filter out in JET fuel tanks but avgas

is lots faster More like the 10 to 15 mins.

I do both orings on each cap every year without fail.

[Guest]

It's very easy to check the caps for leaks, SB M20-229A says to turn off the fuel selector,and the pressurize the tank through the vent. A long length of rubber hose connected to the vent will allow you to blow air into the tank by mouth while spraying some soap and water on the cap.

Clarence

[jetdriven]

Those blue Flourosilicone O-rings last at least 5 years and likely 10-15 years.  Sure they cost a few bucks more, but they dont get cracks and get hard like the plain rubber O-rings get. they simply dont wear out.

 

My bladder caps have them standard, and they're the 50 PSI learjet / citation / king air fuel caps.

 

http://www.csobeech.com/fuel-caps.html

[carusoam]

Fuel caps get adjusted at annual.

I think I understand one closes easier than the other?

Expect that the easy one is not sealing properly. Time to adjust the cap.

If you fill the tank to the top, you will see blue streaks emanate from the loose cap.

Reminds me to get one of my caps tightened...

Best regards,

-a-

[Jim Peace]

Those blue Flourosilicone O-rings last at least 5 years and likely 10-15 years.  Sure they cost a few bucks more, but they dont get cracks and get hard like the plain rubber O-rings get. they simply dont wear out.

 

My bladder caps have them standard, and they're the 50 PSI learjet / citation / king air fuel caps.

 

http://www.csobeech.com/fuel-caps.html

My IA would not install them.  Said they were not legal.....

[Robert C.]

Romair,

 

The identical thing started happening to me about 3 weeks ago. Local AP agrees with the general commentary here and is replacing the O rings and adjusting the cap lever tension adjustment screw/bolt today.

 

Robert

[DonMuncy]

Although the blue ones last a lot longer, most IA's read the AD to say that the O rings have to be inspected yearly. And after you take the cap apart, replacing the O rings is almost a negligible cost. And since the IA may not know (or care to look up) when they were last replaced, I suspect your blue ones are likely to get tossed long before they go bad.