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Fuel smell inside Jab 230


Peter008
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Evening folks

 

I have been smelling fuel inside the cab of the jab for a little while but never able to locate the source. Today when opening the door it was overpowering so I again went looking for a leak.

 

I am using premium 98 (BP) and have since purchase 18 mths ago. Previous owner used Avgas. At purchase I had to replace a hose clamp at the fuel tap in the console as it was too big for the job. I have pulled everything apart that I can think of but find no weep or leak. Have looked at fitting on firewall, both sides of tap, electric pump and filter and the 5 ltr tank at the rear to no avail. Pulled the covers off the wing tank fittings and no issues on either side.

 

Obviously it is worse when the wing tanks are full, as they are now. Can there be merit in the thought that the fuel is weeping through the 5 ltr tank and evaporating thus causing the smell? I'm running out of ideas.

 

Has anybody had a similar issue and found the problem?

 

 

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Aromatics in fuel can leach through the walls of certain types of bladder and plastic tanks. The same applies if you do not have quality fuel lines and hose clamps.

 

You will smell fuel if standard plastic jerry cans are stowed in the cockpit as they leach aromatics. It isn't dangerous so long as there is good ventilation. Even if you have vinyl ester glass tanks you can get leaching if the tanks have not been properly sloshed with vinyl ester before assembly and a glass strand is left protruding. Very difficult to see but fuel will seep down the glass strand & evaporate on the outside so you will get the smell. Welded aluminium tanks will eliminate the problem but welds can fail.

 

Nothing is perfect.

 

 

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Peter I have a similar situation. I changed over to mogas about 6 months ago and yes it seems worse. I found slight discolouration at the header tank, have tried using epoxy ribbon while the tank is in situ however it has not improved, if in fact that is the source. I will next remove the header tank so that I can get a good look at the fix and see how that goes.

 

 

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Thanks guys.

 

My next thought was to remove the header tank and give it to someone who may have the solution to slosh in it. Avgas is available where I am so maybe I switch to that and do the tank at the next service due in a month or so at the rate of use lately.

 

From what has been said above it appears that Avgas either will not weep through the tanks as mogas does or it simply does not smell to the same extent.

 

Thanks again for the advice.

 

 

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Yes. I have the same problem in my j400. I have searched but no leaks. Aromatics leach through the header tank is the conclusion I came to. Switching to avgas not a solution as the rotax prefers premium unleaded. I just leave the doors open in the hangar.

 

 

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If I was to line the inside of the header tank as it would have been originally (although with different solution according to the Jab web site) would it also be an advantage to paint the outside of the tank as well?

 

Has anyone asked Jabiru if they have a fix for it?

 

 

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I have the same problem with my 230 and I believe it is related to the fuel tank filler/cap installation.

 

If I happen to overfill or park on an uneven surface and the fuel is able to gravity feed from one tank to the other I have found that the fuel actually leaks out through the wing root (I'm yet to find the reason for this) but I suspect it is to prevent over pressuring the fuel tank, if you look inside the fuel filler point you will notice a row of holes in the metal insert, I think this is where the fuel/fumes are able to pass into the void space in the wing. If this is the case then fumes will be able to transit through the control cable openings from the wing root to the interior of the fuselage.

 

I'm not certain that this is the reason and I'm investigating further.

 

 

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Hey guys, I saw this post a few days back on another forum... have a read.. this guys has a Jabiru.

 

---------------

 

Fuel for Thought

 

Another gremlin has appeared lately; an especially destructive little monster which has started

 

chewing on fuel tanks, causing leaks. Because formulations vary so widely I normally don’t like

 

naming names, but in this case it does appear that Shell V-Power (98 RON) is a common factor in

 

many cases. Indications are that this fuel (and others like it) contain a relatively high proportion of

 

Aromatics: highly volatile compounds, including nasties like Toluene. Unfortunately, the sealant

 

used in our fuel tanks is not suitable for use with compounds like this: Toluene is often used as a

 

cleaner or as paint thinners and is pretty aggressive stuff!

 

Most issues seem to occur in cooler climates where a highly volatile component like Toluene would

 

make sense in assisting cold starting your car after it was parked in the snow all weekend – but we

 

recommend that all operators review Service Letter JSL007, understand the content, the

 

compromises and risks inherent in using automotive fuel. It’s strange to be feeling nostalgic about

 

the “good old days” when the most destructive component of MOGAS was Ethanol, but here we are:

 

there’s progress! Remember, the days of “fill and forget” are gone: there are many traps waiting to

 

bite if you take the contents of your tank for granted.

 

In response to the leakage issues we’ve started a new round of testing with a sealant which we are

 

promised is the last word in chemical resistance: proof against fuels, volatile hydrocarbons and even

 

acids. All going to plan, we will release this product to service as soon as testing is complete. Early

 

indications are that this compound will also be suitable as a retrofit, to re-coat tanks currently using

 

other sealants. In the interim I’d recommend using a 95 Octane fuel instead of 98 as they appear to contain less

 

destructive aromatics. Of course, good old AVGAS is still a lovely stable fuel which doesn’t attack

 

anything but your bank balance – but we realise that it’s not practical for everyone.

 

------------

 

 

  • Caution 1
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The orings in the selector tap shrink, just like on the tank caps.

 

Older models have three taps, newer just one.

 

Easy job to replace but hard to get tap out and newer ones you have to crimp tank hoses to isolate

 

Fuel can overflow and mine runs down the font of the flap, where you cant see and ends up at wing root.

 

 

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  • 2 weeks later...

I had a fuel smell problem with my SK at first.

 

Here's what should work to find the problem: Plug off the vent/s, disconnect the fuel line and pressurize it to a few psi. You could get enough pressure by blowing, and I don't reckon you are making an explosion risk, but use an inert gas if this scares you. The tank and system should hold the pressure. If the pressure is getting lost, use some detergent-water and a brush to investigate where. I hope you don't have a porous tank, wouldn't this weep a bit of liquid?

 

Refrigeration mechanics use this detergent thing all the time to check for gas leaks.

 

good luck, Bruce

 

 

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Keith Rule at Cessnock had exactly this issue with his 230 and using hi octane mogas. He believed that the aromatics damaged the header tank and as a result there are fumes in the cabin.....

 

His view for his aircraft was that the damage was done, changing back to avgas, which he has done, wouldn't undo the damage and he intends shortly as I understand it to replace the header tank......

 

His recommendation to his clients was not to change to mogas for existing aircraft......J will undoubtedly change something for the tanks in the long term...but that doesn't help anyone who already has one......

 

Just waiting for the first big boom when someone does something that sets off the vapour.....

 

The comments above are my recollection of Keiths problem when I discussed changing to hi octane mogas for my 230 after he had finished overhauling my 3300....they are recollection and as such may be wrong....

 

Andy

 

 

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  • 2 weeks later...

If you can smell gas in the cockpit then you could be in a flying bomb, just waiting for that spark to set it off.

 

If so many jabs have the problem, Jabiru must identify the source and make available a permanent fix. Don't wait until too late.........splat.gif.4fe5615d47cdda8649f5910181ed23f2.gif

 

 

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I though Jab has approved the use of mogas above 95. it's in my manualCheers Rory

The thing is approving Avgas today will almost certainly be applicable tomorrow because the contents of avgas wont have changed. Approving Mogas today means nothing tomorrow because then major brand names all have a slightly different recipe that seems from what we are told can vary between locations and at different times as "new and improved" cost cutting formulae changes are applied....The approval that J provide in their manuals is for what exactly?

 

Andy

 

 

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Yep jabs are proved for use with Mogas.

 

But I had problems with smell in my j430 for a while and found it was at the lower outlet in the wing root.

 

If I can suggest - firstly convert back to avgas for a while and then recheck all your connections hose outlets etc. the green blue dye makes finding leaks much easier.

 

 

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Had fuel smell for quite a while, could not see any leaks, last week fuel all down the side of plane. Removed wing re sealed tank replaced fuel lines , under header tank is fuel stain and wondering what to do with it. The J230 was sitting for a couple of weeks so I believe that to have caused the leak. I use 98 shell and Avgas depends where I am. Undecided what to use but need to fill up tommorow and thinking 95 but which is the best brand ?

 

 

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