Fuel smell

[Oscar Avalle]

I have a question. For a while after I shut down the engine and only if I am running on the left hand tank (pilot's side) and it is hot (ambient temperature above 80) I can sense some fuel smell in the cabin. I looked for marks of fuel and everything looks clean... Any suggestions or ideas? Sent from my iPad using Tapatalk HD

[mike_elliott]

Hi Oscar, the inboard senders sometimes leak slightly causing a fuel smell in the cabin. Remove the interior side panels and check these. You can typically just tighten the screws up on them to fix it if this is your issue. Other areas to check is the gascolater for leaks and the fuel pressure gauge fitting.

[Marauder]

Hi Oscar, the inboard senders sometimes leak slightly causing a fuel smell in the cabin. Remove the interior side panels and check these. You can typically just tighten the screws up on them to fix it if this is your issue. Other areas to check is the gascolater for leaks and the fuel pressure gauge fitting.

I'll second that... My last two "fuel odor in the cockpit" scenarios were the sending units. Another area to check is the fuel selector switch.

[Oscar Avalle]

Thanks will do

[MB65E]

Ours had an incorrect oring installed after the dukes pump overhaul. Changed oring, no smell. Lots of lines (fuel/brake)under the left seat floor boards. Some are hard to get a wrench on. If its smells, you'll see blue...

-Matt

[jlunseth]

Yeah, unfortunately it is also possible for fuel leaking from a tank to flow to the wing root, which is inside the cabin. It is viewable by removing the interior sidewall and it may be necessary to remove the floor also. I would look at other sources first, and then have the wing root checked at annual since the mechanic will do that dissassembly at that point.

[AmigOne]

My C had the smell when I bought and I knew what it was. I ordered two rubber gaskets for the fuel senders from Lasar,I think something like $8. The gaskets have holes that match the screws that hold the fuel sender to the wing root. I did it myself (with A&P supervision of course) and saved lots of labor because a lot of things have to come out in order to access the senders, nothing from the floor though. Also I used as much fuel as I dared in flight and removed whatever was leftover. After I removed the side panels I could observe the stains surrounding the sender where fuel had been leaking for a while. It should have been caught during an annual, but the airplane had been sitting in between annuals because the owner had died after a long illness. It was an issue, among others, for price negotiation.

[scottfromiowa]

Well done! Pretty significant before and after view there.

[rockydoc]

Don't mean to show my ignorance, but I have the same problem on one tank and would like to first check my "fuel senders."  What are they, where are they and how do I get access to them on each wing?

Thanks for bearing with me.

[Marauder]

Don't mean to show my ignorance, but I have the same problem on one tank and would like to first check my "fuel senders." What are they, where are they and how do I get access to them on each wing? Thanks for bearing with me.

The fuel sender units are the sensors use to detect fuel levels and are behind the side panels inside the cockpit. You will need to remove part of the interior to get access to them.

[DonMuncy]

I don't know about all models, but my K has an inboard and outboard sending unit on each tank. It is not a big job to get the interior panels off to get to the inboard ones (right under the door), and the outer ones are accessible via a panel under the wing. Those are a bit more trouble to get to.

[isaacpr7]

My C had the smell when I bought and I knew what it was. I ordered two rubber gaskets for the fuel senders from Lasar,I think something like $8. The gaskets have holes that match the screws that hold the fuel sender to the wing root. I did it myself (with A&P supervision of course) and saved lots of labor because a lot of things have to come out in order to access the senders, nothing from the floor though. Also I used as much fuel as I dared in flight and removed whatever was leftover. After I removed the side panels I could observe the stains surrounding the sender where fuel had been leaking for a while. It should have been caught during an annual, but the airplane had been sitting in between annuals because the owner had died after a long illness. It was an issue, among others, for price negotiation.

AmigOne,

My fuel sender area looks exactly like the picture you posted. Can you give me any tips on how to replace these gaskets? What did you use to clean the area and make it look so new?

[Bob - S50]

I have a question. For a while after I shut down the engine and only if I am running on the left hand tank (pilot's side) and it is hot (ambient temperature above 80) I can sense some fuel smell in the cabin. I looked for marks of fuel and everything looks clean... Any suggestions or ideas? Sent from my iPad using Tapatalk HD

I hate to go counter to the suggestions, but I would be more inclined to think it was the selector valve.  If it was a leak at the sending unit or where the line comes through the sidewall, I would think the smell would occur all the time.  But you said it only occurs when you have the left tank selected.  To me that indicates maybe a leak in the selector valve that only occurs in the left position.  I'm also guessing you only smell it after shutdown because airflow and other smells mask the smell of fuel with the engine running.  I'm also guessing that the high temperatures help to vaporize the fuel so that it spreads more quickly and makes it more noticeable.

 

Good luck,

 

Bob

[flyboy0681]

A month ago I freaked out when I climbed in and smelled fuel. I did a visual inspection inside (but didn't remove any panels) and found nothing. After letting it air-out for an hour it dissipated and I flew off.

 

That was the one and only incident and since that time - nothing.

[tomn]

A month ago I freaked out when I climbed in and smelled fuel. I did a visual inspection inside (but didn't remove any panels) and found nothing. After letting it air-out for an hour it dissipated and I flew off.

 

That was the one and only incident and since that time - nothing.

I would bet that it had been cold when this occurred. I'd check the sending units first for your issue then proceed to other areas as mentioned above. I have had the same thing occur while on a trip up north to colder area when the plane sat overnight. Tightening sending units fixed it.

[flyboy0681]

I would bet that it had been cold when this occurred. I'd check the sending units first for your issue then proceed to other areas as mentioned above. I have had the same thing occur while on a trip up north to colder area when the plane sat overnight. Tightening sending units fixed it.

 

We did have a cold snap at the time, so you may be on to something.

[SkyPilot]

I had to replace one of the sending unit gaskets during the first annual. They are cheap. Draining the fuel is required however

 

Last week we did another annual and found a few leak at the filter ahead of the Dukes pump. It ended up being a pipe flange and was easily fixed by my mechanic.