Fuel Smell in the Cabin

[jaredyates]

Something I've been stumped with is a smell if fuel in the cabin, and I wonder if anyone else has any ideas. It seems worse when the tanks are full. I have visually inspected the inboard tank ports all the way to the firewall and can't see any wetness. I thought maybe fuel was venting and flowing down the filler neck but after adding a seal there it still persists. I can't find any blue stains anywhere. Does anyone have any ideas for other things to check?

[marcusofcotton]

While parked or flying? Certain flight attitudes worse? Any rubber fuel lines that are not CARB compliant? Primer system?

[Utah-Jay]

Deals on the sight gauges?

I am hatching a plan to test mine before I install them in my wing root panel

[Nev]

My sight gauges seeped when I first installed them so I added a hose clamp on each one.
I've also had a fuel smell from the doors opening and they can press against the fuel drains which then allows fuel to run down the window.

[jaredyates]

These are all good leads, thank you. There aren't any rubber lines and the sight gauges are dry. We have at times smelled it in flight but it is more faint due to the airflow I would imagine.

[Richard E]

One of our sight gauges seeped until we replaced them with the rigid pvc like on the first Bearhawk 5. Since then, no problem.

[Rollie]

Could be the line connecting the sight gauge to the tank, probably one of the top ones if its only when your tanks are full. That would put the leaking fuel in the wing root instead of dripping down the sight gauge. Easy enough to pull the wing root fairing and put a wrench on each fitting to make sure everything is still tight.

[kestrel]

You didn't say when you were smelling fuel. In my experience, full tanks seem to result in fuel splashing out the vents in the caps when taxiing with the smell easy to notice.

[Helidesigner]

Same as Kestral, I sometimes smell it when taxiing with full tanks. I think it is fuel sloshing out the vent holes and getting into the fuel tank compartment. It goes away as soon as I take off. My fuel sight gauges have no signs of leakage.

[jaredyates]

Great news, it took a while for the blue dye to show up on a very slow leak but I finally found the problem. It was a flare union that was tight but not quite tight enough. I've fixed that and with any luck tomorrow morning will be greeted by a non-fuel-smelling airplane.