fuel oil smell in cockpit

[kitfoxflyer]

I have kitfox model1V 1200 fitted with rotax 912 ,she flies beautifilly but at end of flight my clothes and everything in the cockpit smell of fumes. there are no visible fuel or oil leaks from engine or fuel system, is fitted with two fibreglass 13us gallon wing tanks and plastic header tank behind seat.the fire wall is well sealed .there seems to be a slight fuel smell during climbout whilst on maximum power which reduces with a small reduction in power.could anyone help with
a solution

[Esser]

Have you checked your exhaust fittings? Where does your exhaust terminate?

[Av8r_Sed]

Do you have any pressurized fuel lines in the cockpit, or is it all gravity feed? Do you have a mechanical fuel pressure gauge in the panel? These can be sources for leaks when you're flying.

If you're using rubber fuel lines to connect the wing tanks, it's a good idea to use non-permeable hose such as Gates Barricade or similar.

[SWeidemann]

I too noticed on my first flight ever in my newly acquired KF Vixen with 912 ULS (on the ferry flight home from MA to WI). My observations too. I expect to find out more soon because I will be changing out my engine mount. My expectation is some sort of exhaust leak or possibly exhaust coming through the floorboards from the high angle of attack during one of those high performance high angle of attack climbs. I'll report back if I find out.

Skot
Vixen N24V

[kitfoxflyer]

Thanks for your replies, My exhaust system is standard rotax muffler which exits
lower left cowling slightly in front and to left side of radiater scoop.
I do have an electric fuel pump installed behind the baggage sack area,but only use this on first start up. the fuel hoses from tanks to header tank are automotive type Gates SAE 30R7 CS0710407 X2 not for fuel injection.
Even when in hangar when open cabin doors a strong petrol oil type odour is present, could the plastic header tank be emitting fumes?

Tony
Kitfox 1V 1200 Ser DCU024
Rotax912
Tricycle undercarriage.

[Av8r3400]

I'd be more worried about the fiberglass wing tanks than the plastic header tank.

In your area, is there ethanol in the gasoline? If so, it may have damaged your wing tanks, causing leaks.

[Av8r_Sed]

Try swapping to the Gates SAE 30R9 product. The 30R7 hose is especially bad if there's Ethanol, but then your fiberglass tanks could be in trouble too.

[cap01]

sounds strange but i had the same thing with the gas smell in my model IV . i replaced the hoses with parker non permeable hose and that took care of it

[kitfoxflyer]

I am going to try fitting new fuel lines from tanks to header , I will let you know the results. AS far as Im aware i have not put any fuel in that has contained ethanol
Tony
Model 1V1200

[cap01]

you need to replace all the rubber hoses if not youll still get the smell . at first i replaced all my hoses except about a foot on each side of the header and i still had the smell until it replaced them .

[HighWing]

Tony,
Also check the fittings at the Poly header tank. These are notorious for weeping. Try wiping around the fitting with a paper towel and check for fuel stains or moisture on the towel and the nose test. Unfortunately with these fittings you are pretty much between the proverbial rock and a hard place. Not tight enough and they weep, two tight and they strip the threads and they weep. Also, there are thread sealants that work better than others - you might want to check the archives. Lots of effort over the years trying to make these things work.

[n85ae]

The headers just plain breathe. I've yanked my seat a half dozen times trying to kill fuel
smell to no avail. So now I just leave the doors open in the hangar so it stays aired out.
One day I'll embezzle enough from checking/savings that my wife doesn't see, and buy
an aluminum header.

Regards,
Jeff

[Dave S]

Everything that has been said about the permeable auto fuel hose and potential leaking fittings on the poly tank are true.

I want to add another potential issue related to the poly header tank as I ran into a unique situation with mine. First off, my poly header tank was a product of the old defunct sky#%@&/EGT company and the one I recieved was sent to me just before I got the bankrupcy letter from sky#%@&'s/EGTs attorney. I am speculating sky#%@&/EGT was cleaning out the shop of old junk and passing it off just before the bankrupcy - the fitting holes were not straight either. Definitly some QC problems on the poly tank I had.

The poly tank I had continued to stink up the cockpit like a skunk....even after I replaced the permeable auto fuel hose with the good stuff. Somewhat puzzled after finding no fitting leaks of any kind, I removed the header tank, dumped and cleaned it and examined it carefully. What I found was several big bubbles in the poly casting which basically provided that there was no more than a couple thousands of an inch between the interior of the cockpit and the inside of the fuel system - the "nose test" confirmed this was where the stink was coming from.

John Mc Bean was just starting to make the aluminum header tanks at the time...got one of those from him and that solved all the fuel stink problems. John got it right with the aluminum header tank and it has done its job flawlessly ever since....no problems.:)

Not saying that you may have the same or similar issue, just to share that this is another potential deal a person may or may not run into on the poly header tank.

Using the recommended sealer everywhere on the fitting threads throughout the fuel system is good to do too.:)

Sincerely,

Dave S
KF7 Trigear Flying
912ULS Warp Drive

St Paul MN

[DesertFox4]

Dave, I agree completely with your findings.

Since 1999 when Murle Williams made my first aluminum header tank I've never considered using the poly header tank. Too many instances of leaks and fuel vapor smells inside cockpits. :eek:
The aluminum header tank also gives you just a little more fuel volume which means if your low fuel warning light comes on you have a little extra time to get back down safely but please don't test this feature if you can avoid it.;)

John has offered the aluminum header tank for some time now as an option. They are a good investment and will give you piece of mind that your header tank will not be cause for an interrupted trip.

[Jwayneball@aol.com]

I just bought a beautiful Kf III. Despite a long extension on the exhaust pipe, I still get exhaust into the cockpit. There doesn't appear to be leaks in the system elsewhere. The plane has the Rotax 582. Anyone have any solutions?
Thanks,
Wayne

[Av8r_Sed]

I'm flying a Model III, 582 and don't get exhaust in the cockpit when flying. I might get some oily smoke during warmup but it's a non-issue after I start taxiing.

I spent a fair amount of time lapping my exhaust elbow to avoid leaks. That and a thin application of anti-seize to allow the joints to move. Also, I used a little high temp RTV on the exhaust manifold gaskets to seal everything up nice.

[beeryboats]

I just bought a KF IV last weekend and it needs a lot of work. New engine, and change all the rubber stuff like hoses. It's been setting for 10 years. This thread is a truck load of info for me to digest before I start purchasing stuff. It has the 582 engine which I think I'll have rebuilt vs. the 912. After reading this thread, can anyone recommend any other fuel related issues? On thing that is a little of an unknown at this point is a fuel leak stain down the right side door right below the fuel line. I thought it must be a bad line, but it now sounds like it could be a bad tank??? I sure hope not, it looks like the wing would need to be opened up to replace a tank.

[Av8r_Sed]

With the tanks drained, take a good look inside at their condition. If you can, use a fiber optic inspection scope to look around. Other threads have mentioned ones that are inexpensive and work well. You're looking for peeling sloshing compound or other loose crud.

Make sure the tank drain is OK. You may be able to replace an O-Ring or maybe the whole drain fitting will need replacement. Use a good sealant when replacing the threaded fitting. Others have used Permatex aviation Form a Gasket Sealant 80017(3D) or 80019(3H). I used Dow Corning 730 RTV sealant which worked great, but is excessively expensive. Also it would be a good time to reseal the vent and outlet fittings.

Your wings should have some drainage holes near the trailing edge, principally to handle any water in the wings. Make sure there is a way to drain away any leaks before adding gas.

Leak test each tank (probably outside). I'd rig up a temporary valve and good tube to the outlet so you can drain it quickly if it is leaking. Then start filling gradually with ethanol free gas and see what happens. in general, some leaking fuel won't hurt your fabric, but it will damage Lexan. If you're seriously worried, remove your doors and upholstery beforehand.

Hopefully, it's something simple.