Fuel leak?

[Poptimes4]

Long time listener, first time caller.

I'm in a partnership on a M20f. Great plane and good avionics package including dual aspens. Over the last year or so, we have noted the right tank loses up to 10+ gallons if she sits without flying over say a 2 week period. No fuel staining is noted on the floor. My partner feels there may be a void within the fuel system that is slowly filling over that time while I think there’s an internal leak with evaporation. Either way, I don’t like it.

 

I wondered if anyone else  has any experience with this type issue. It’s going into annual later this month. The last guy to look into this didn’t find anything.

 

Thanks

[Clparker23]

I had a leak at the fuel sender and it was hard to see, look under the carpet in the back seat area. I pulled the side panels off the passenger side and finally discovered the leakage.


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[N201MKTurbo]

There has to be stains somewhere. Or somebody is stealing your gas. 

[David Lloyd]

10+ Gallons over two weeks should be pretty easy to smell and likely see the stains.  I have had fuel recently evaporate from my boat in a similar fashion.  So have my neighbors.  Hmm?

[Guitarmaster]

That's a lot of gas to be losing in 2 weeks without evidence of a leak! . Mine has sat for a month before and not lost a drop.
I think I would go with the theory that somebody stealing your gas.
Do you keep your tanks full? I have had it piss out of the fuel vent before. But 10 gallons?

I will be anxious to hear the outcome of this! Good luck with the sleuthing!

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[Poptimes4]

Thanks everyone. I suspect we’ll see something when we pull the seats and get under the carpet.

[Jim Peace]

22 minutes ago, Poptimes4 said:

Thanks everyone. I suspect we’ll see something when we pull the seats and get under the carpet.

That is too much gas not to smell it right away.....get a battery operated security camera and put it in the plane facing the wing.  tape up the LED lights so as not to be visible ...

Swann and other companies make them....

[powder_hounder]

You might try stick the tanks with a piece of wood and note the fuel level when you leave the plane sit for a while and do it again the next time you fly.

 

Like the others, 10 gallons is too much fuel for you not to notice or smell.

Edited September 9, 2018 by powder_hounder

[Yetti]

There is an inspection panel on the bottom leading edge of the wing about 1/3 of the way out from the cabin.    You can take a look in there.   Flush mounted panels with flush screws usually mean a fuel tank panel.  Don't pull those.

Edited September 9, 2018 by Yetti

[MyNameIsNobody]

We had a very pronounced fuel smell in cabin and we were NOT losing ten in Two.  My guess is somebody is stealing your fuel.  

[Stephen]

7 minutes ago, MyNameIsNobody said:

My guess is somebody is stealing your fuel.  

Let us know what you find under the carpet.    Per @MyNameIsNobody and others here I believe you would reeeeallly smell it if there was an in cockpit leak at that rate...and there would be significant stains.

@Poptimes4 are you on the ramp or in a hangar? Good news you *may* not have a leak ; bad news is you may have to do some additional physical security.

[bonal]

1 hour ago, MyNameIsNobody said:

We had a very pronounced fuel smell in cabin and we were NOT losing ten in Two.  My guess is somebody is stealing your fuel.  

That would be my first thought. Especially if your on the ramp

[Poptimes4]

We are in a closed hangar. I do get a nose for fuel when first getting the plane opened up but it clears once I pull the plane out and get her going. I’ve asked a couple of folks what they thought of it but they thought it was not outside the norm.

[MyNameIsNobody]

1 hour ago, Poptimes4 said:

We are in a closed hangar. I do get a nose for fuel when first getting the plane opened up but it clears once I pull the plane out and get her going. I’ve asked a couple of folks what they thought of it but they thought it was not outside the norm.

Since tanks and senders sealed ZERO fuel smell.  Used to be your scenario.  Our carpet in rear was “blue”.

[Poptimes4]

We are in a closed hangar. I do get a nose for fuel when first getting the plane opened up but it clears once I pull the plane out and get her going. I’ve asked a couple of folks what they thought of it but they thought it was not outside the norm.

[carusoam]

I didn’t finish this post.....

 

but since we are discussing it still...

 

Welcome aboard Pop.

Get ready to pull inspection panels.  A normal activity for annual.

all leaks leave stains.

The most common and easy to fix, leaves a stain under the carpet.

If you have a stain under the carpet, you would smell it each time you open the cabin door to enter...

I thought my plane smelled like really old airplane...  

That really old smell is 100LL...

 

 Here’s the new part today...

Are you able to use a screwdriver?

It is pretty easy to pull a side wall panel or two...

Unfortunately things only get worse with time.

Get on it! It’s probably a $5 fix. 

While you are there... look at two things...

1) the rubber seal for the fuel level sensor...

2) the rubber connector on the fuel line...

3) also in the neighborhood... low pressure rubber hose for the hydraulic flaps (if you have hydraulic flaps)

All the original rubber bits had a tendency to harden and crack.  Take a look at yours to see what they look like.

 

Trying to spread good news regarding early ownership experience.... not fear mongering...  

Many rubber bits are really inexpensive... better to swap out, then fear fuel vapors in the cockpit...

Having 10gallons go missing... means a serious problem may still be there...?

in the cockpit with you... or in the wings with some wires...

 

PP thoughts only, not a mechanic... stuff I learned from an M20C, before MS was available...

Best regards,

-a-

[Poptimes4]

Great info! Thanks for the input. Will do.