Fuel Staining on back seat floor

[TigerMooney]

1981 M20J

I noticed some light staining on the underside (not the top) of the carpet in my rear seats, and also around the floor. 

My plane is going in for annual next month. I noticed in a Pre J model forum that this was either from some very old hosing or the fuel sending unit. Has anyone else dealt with this in a J? Is there anything I can do (parts I should order) or info I can relay to the mechanic before we commence the annual?

 

Thanks

[StevenL757]

I know others on here are likely to answer this easily; however, I'd personally run this by Paul Beck at Weep No More.  He'll give you an estimate based on the magnitude of your situation so you know what $$ will likely need spending, where, and when so you can plan accordingly.

[EricJ]

27 minutes ago, TigerMooney said:

1981 M20J

I noticed some light staining on the underside (not the top) of the carpet in my rear seats, and also around the floor. 

My plane is going in for annual next month. I noticed in a Pre J model forum that this was either from some very old hosing or the fuel sending unit. Has anyone else dealt with this in a J? Is there anything I can do (parts I should order) or info I can relay to the mechanic before we commence the annual?

 

Thanks

Same issues in a J.   The fuel pickup and hose run right through there, and the inner fuel sender is right there as well, just like on earlier models.   It's most likely not a big deal to fix, but definitely worth getting done.

[mike_elliott]

A lot of times simply tightening the screws on the inboard sender will fix. The gaskets are like me, old and shrunken. Hopefully it doesn't require Paul Becks fully articulating hands and scrapers. He can supply new gadgets and rubber fuel lines. He is good people 

[Shadrach]

First thing to determine is if it is staining from a previous leak that has been repaired or a new leak. To my mind, a leak like that would be accompanied by a pretty strong fuel smell in the cabin if it were still flowing.

[Yetti]

mostly likely is tighten the fuel line clamps  or tighten the fuel sender screws.

 

the fuel sender gaskets if they need replacing Can be obtained here.    Buy 4 of them.   https://www.brownaircraft.com/aviation-seals-s/22.htm?srsltid=AfmBOoq4PgLntrAGGd8uj18tsDPYQQ53_MC1d7Z9TFX3Uy9fuKhAefWD

You can also get the Gasket for the fuel coolator from them.  So order that too.

[PT20J]

8 hours ago, Shadrach said:

First thing to determine is if it is staining from a previous leak that has been repaired or a new leak. To my mind, a leak like that would be accompanied by a pretty strong fuel smell in the cabin if it were still flowing.

Last summer I noted a faint fuel odor in the cabin when the airplane had been sitting for a day or so closed up in the hangar. I traced it to a tiny seep from a screw attaching the right outboard fuel sender. The vapor travelled all the way down the leading edge of the wing to the cabin. So, it doesn't take much to be detectable by smell. A big leak will definitely be noticeable. And, BTW, if you think all that duct tape covering the gap at the wing root will keep CO out -- it won't.

[Shadrach]

Just now, PT20J said:

Last summer I noted a faint fuel odor in the cabin when the airplane had been sitting for a day or so closed up in the hangar. I traced it to a tiny seep from a screw attaching the right outboard fuel sender. The vapor travelled all the way down the leading edge of the wing to the cabin. So, it doesn't take much to be detectable by smell. A big leak will definitely be noticeable. And, BTW, if you think all that duct tape covering the gap at the wing root will keep CO out -- it won't.

I know all too well. I did clean and retape all of the gaps under the wing root fairings about 10 years ago. The original tape had completed delaminated leaving a yellow powdery mess on the aluminum.

[RoundTwo]

Pulling side panel will quickly tell you hose, sender or sealant.

[Fly Boomer]

3 hours ago, PT20J said:

And, BTW, if you think all that duct tape covering the gap at the wing root will keep CO out -- it won't.

Will anything reasonable keep it out, or do we depend on other cabin leaks into the slipstream to siphon it out?

[PT20J]

3 minutes ago, Fly Boomer said:

Will anything reasonable keep it out, or do we depend on other cabin leaks into the slipstream to siphon it out?

The best thing is to make sure that the muffler is sound -- that's the main source of it getting into the cabin. In flight, the airstream should carry the exhaust away from the cabin.