Fuel fumes

[rturbett]

1980 m20 j

noticed fuel smell in cockpit - not outrageous, but noticeable. 
dissappated quickly.( or I got used to it)

no leaks observed

anyone else experience this?
thanks 

Rob

 

[Fly Boomer]

3 minutes ago, rturbett said:

1980 m20 j

noticed fuel smell in cockpit - not outrageous, but noticeable. 
dissappated quickly.( or I got used to it)

no leaks observed

anyone else experience this?
thanks 

Rob

 

I have not dealt with it (yet) but from what I read, it is frequently one or both fuel senders in the wing root.

[PT20J]

One sender is in the root; the other is at the outboard end of the tank. Either can cause an odor in the cabin. The one at the root is obviously in the cabin. But there is a path along the leading edge of the wing for the gas to go downhill into the cabin. I’d check outboard first because you don’t have to remove interior panels. Look for blue fuel stains. 

Skip

[JModelDave]

You can also check the area around the wing sumps, inboard gear well and the belly pan next to the sumps for blue stains. We had a K model in our shop last month weeping at the inboard rear corner of the tank and the owner was smelling fuel in the cockpit..

[Ragsf15e]

20 hours ago, rturbett said:

1980 m20 j

noticed fuel smell in cockpit - not outrageous, but noticeable. 
dissappated quickly.( or I got used to it)

no leaks observed

anyone else experience this?
thanks 

Rob

 

What phase of flight were you in?

Were you leaning for cruise?

Edited December 7, 2023 by Ragsf15e

[rturbett]

8 hours ago, Ragsf15e said:

What phase of flight were you in?

Were you leaning for cruise?

just parked in hangar

[ArtVandelay]

One sender is in the root; the other is at the outboard end of the tank. Either can cause an odor in the cabin. The one at the root is obviously in the cabin. But there is a path along the leading edge of the wing for the gas to go downhill into the cabin. I’d check outboard first because you don’t have to remove interior panels. Look for blue fuel stains. 
Skip

The inboard senders are just in front of the rear seats, OP might be able to just pull the corner of the carpet up to check the floor to see if any blue stains from fuel dripping from the senders without removing any panels.

[Ragsf15e]

9 hours ago, rturbett said:

just parked in hangar

Yeah, then you’ll need to check behind the carpet below the door line as others are saying..  there’s a whole technique to fixing leaks around the inboard senders or pickup.  Once you find the leak, look for that tread on this site.

[Mark89114]

My fuel pickup line was leaking....all in the same area as the fuel senders.  

I would only get a whiff when making a right hand descending turn, guess the air flow would push more of the vapors into the cabin.  Bought the new gasket, followed instructions for install from a MSC, no sealant and it still leaked even thought I assume the original factory install had sealant all over it.  Ended up using fuel sealant anyway.

 

[Joe Linnebur]

On 12/6/2023 at 4:32 PM, PT20J said:

One sender is in the root; the other is at the outboard end of the tank. Either can cause an odor in the cabin. The one at the root is obviously in the cabin. But there is a path along the leading edge of the wing for the gas to go downhill into the cabin. I’d check outboard first because you don’t have to remove interior panels. Look for blue fuel stains. 

Skip

I’m dealing with the same thing. I removed the cockpit side panel and found evidence of fuel (left wing) in the side panel area, but the seep seems to dissipate when the fuel is below 25 gal. The sender and fuel line in the cockpit area was dry with no stains, which leads me to think the other location you speak of might be the culprit. 
 

I have noticed fuel staining now along a seam in front of the main gear, which is in line with where the fuel float is located. Any further recommendations would be appreciated. 

[PT20J]

I would remove some inspection panels and look inside the wing and see if you can locate where the fuel is coming from. On some models, some of the panels that are not routinely opened are pop riveted so you might need to drill some rivets out. Replace them with countersunk rivets.

[Joe Linnebur]

Good to know. I’ll look around next time I’m out there. Thanks for the info!

[Joe Linnebur]

Sorry to revive this thread, but a quick question on replacing the gasket for the outboard sender.
 

After pulling the inspection panel, it’s obvious that the gasket needs replacing (finally, an answer). When the 5 screws are removed (after removing the wire connector in the middle), does the actual indicating unit in the fuel tank remain attached and in-place, or does it require to be held in position during this process? 
 

Id prefer not to assume when we start going through the replacement process. Thanks for any feedback 

[N201MKTurbo]

31 minutes ago, Joe Linnebur said:

Sorry to revive this thread, but a quick question on replacing the gasket for the outboard sender.
 

After pulling the inspection panel, it’s obvious that the gasket needs replacing (finally, an answer). When the 5 screws are removed (after removing the wire connector in the middle), does the actual indicating unit in the fuel tank remain attached and in-place, or does it require to be held in position during this process? 
 

Id prefer not to assume when we start going through the replacement process. Thanks for any feedback 

Don’t worry about it, it probably won’t fall off, it will probably be stuck to the gasket. Even if it does fall off, it won’t hurt anything.

[EricJ]

11 hours ago, Joe Linnebur said:

Sorry to revive this thread, but a quick question on replacing the gasket for the outboard sender.
 

After pulling the inspection panel, it’s obvious that the gasket needs replacing (finally, an answer). When the 5 screws are removed (after removing the wire connector in the middle), does the actual indicating unit in the fuel tank remain attached and in-place, or does it require to be held in position during this process? 
 

Id prefer not to assume when we start going through the replacement process. Thanks for any feedback 

It comes out as an assembly.   The float and the sender are all a single assembly that will come out after removing the screws.

[N201MKTurbo]

Make sure you drain your tank before removing the sender. 

[Joe Linnebur]

32 minutes ago, N201MKTurbo said:

Make sure you drain your tank before removing the sender. 

Yea, it’ll get drained when the time comes. I was having difficulty “seeing” how the gasket gets seated but my brain finally understands. Remove wire, remove screws, pull entire unit out of tank through the inspection panel, remove old gasket/clean mating surface, install gasket, re-install unit, screws/torque, etc. I’m a task card kinda person. Thanks for the feedback

[M Terry]

I had a similar issue, found fuel at the inboard senders in front of the rear seat. I just gave each of the screws a quarter turn and the smell went away

 

[William Munney]

On 12/6/2023 at 5:32 PM, PT20J said:

One sender is in the root; the other is at the outboard end of the tank. Either can cause an odor in the cabin. The one at the root is obviously in the cabin. But there is a path along the leading edge of the wing for the gas to go downhill into the cabin. I’d check outboard first because you don’t have to remove interior panels. Look for blue fuel stains. 

Skip

Yes.  This.  How do i know this is correct?  Because I tore out my carpet when i smelled the sweet odor of 100LL and found blue stains everywhere.  Paul Beck is sealing my tanks this year but now i have to patch it to get my by.

Leaks anywhere from wingtip to root will follow the spar towards the root where the carpet evidently wicks it into the cabin.  Nice.

I hear there are only Mooneys currently leaking fuel and those that will leak fuel.  I think that sucks but you may only deal with it once every 20 years or so.

Don’t burn in your airplane, take care of it now.  The blue stains will lead the way.

Edited January 5, 2024 by William Munney