Gooseneck Fuel Vent Cap?

[sea1dww]

I was reading one of the older (3rd quarter '01) 170 news. There was mention of placing a rubber, or similar material, cap over the gooseneck vent to keep critters out. The stipulation was that a vented cap be installed on each wing tank.

I wonder if this would help with fuel leaking from the fillernecks in flight. I'm guessing that the gooseneck vent has a tendency to pressurize the tanks in flight and the cessna vented caps allow for relief of that pressure and fuel leaves with it when the tanks are full.

Is there any hazard associated with capping the gooseneck vent provided the proper cessna vented caps are installed on the wing tanks?

Dave

[Bruce Fenstermacher]

One hazard is that an FAA type would realize that you did it and want you to provide him with the basis of authority that allowed the change.


The bug in the gooseneck thing is easily fixed. i have a piece of nylon screen from an old screen door neatly folded over the front of the inlet and held on with a tie wrap. Mine has been on for 5 years.

GAHORN has a more elegant solution with a little screen filter he found.

Neither solution I suppose has any strict basis of approval but its a heck of a lot simpler to return to the stock configuration and doesn't change the system.

[cessna170bdriver]

I wonder if this would help with fuel leaking from the fillernecks in flight. I'm guessing that the gooseneck vent has a tendency to pressurize the tanks in flight and the cessna vented caps allow for relief of that pressure and fuel leaves with it when the tanks are full.

Dave

The vent on the cabin roof cannot overpressurize the tanks, and there is no reason to relieve pressure in the tanks. If your fuel caps (vented or not) are leaking, then you have a problem with the cap. The vented caps have a small rubber flap, visible on the inside of the cap, that acts as a check valve to let air IN without letting fuel out. If fuel is getting out of a closed cap, check this valve. Or, more likely, check the rubber gasket in the cap that seals against the filler neck. If it's cracked or worn, the cap can leak. Another possibility is that the seal where the "scupper" (the concave piece around the filler neck) is attached to the tank is leaking.

Miles

[GAHorn]

Yep....what they said.... Do not plug or otherwise restrict the gooseneck's ability to vent.
I believe you/someone has mis-read the intent of any cover for the gooseneck. The airplane should not be operated with the gooseneck vent plugged or covered.

[sea1dww]

I ended up buying new caps. They seem to be different than the current ones, but they are the Cessna vented fuel cap. I will leave the gooseneck alone for now except for the nylon screen to keep the critters out. If the wings continue to get stained, I'll have to look at the filler neck seals. That sounds like quite a job, and I'm not looking forward to having to do it. Anyway, thanks for the feedback. As another member has said, "Ownership is an education".

Dave

[GAHorn]

It'd be a remarkably bad piece of luck (for both of you) to have a bug actually hit the center of the gooseneck in-flight. I have had a mud-dauber-type of wasp build a leafy "cigar" within the vent system of my C-206. It was nowhere near the entrance, but was about 3 feet away from the underwing vent, right up against the check-valve at the tank connection. He clearly didn't like the smell of gasoline, so he built a "dam" or "cigar" that plugged that vent very effectively. (I noticed the fuel pressure having wild fluctuations in-flight, so I switched tanks. Good thing I noticed and checked into it. Those sort of things have been known to completely collapse fuel tanks and wet-wings. I once had a Baron "flame-out" on a go-around at night due to a mud-dauber's nest. Hitting the boost-pump got the engine back, and it was fortunate that the Baron had bladder tanks.)
My little "screen" (from the pick-up tube of a TCP canister) fits inside the gooseneck and is practically invisible.

[six.zero.charley]

What's a TCP cannister?

[bradbrady]

What's a TCP cannister?

TCP is a lead scavenger to add to 100 LL so not to load up the plugs and valves of our older and some newer engines. the older cans had a (I belive brass screan) that works well in this sitution the new (at least quart cans are now plastic and fill one ounce at a time (squeese the continer and fill the one ounce continer dump then fill agian as needed) so be looking for old TCP cans
brad

[GAHorn]

What's a TCP cannister?

TCP is a lead scavenger to add to 100 LL so not to load up the plugs and valves of our older and some newer engines. the older cans had a (I belive brass screan) that works well in this sitution the new (at least quart cans are now plastic and fill one ounce at a time (squeese the continer and fill the one ounce continer dump then fill agian as needed) so be looking for old TCP cans
brad

The screen was fine-mesh stainless.