Hi,

My Engine is leakink fuel pretty bad, from behind the blue cowling. I checked all festos and they seem allright. I replaced the 4MM tubing on the fuel and gas ports (the ones where the 90 deg festo fitting clamps onto).
I cannot run the engine without the cowling to see the direct source of the leak, because it has the strater motor attached to it. Even whith the bad leakeage problem, engine runs fine........but it makes a mess on my airframe every time. I am 100% sure that the leak is happening behind the cowling. Any ideas?

Thanks,

David

Anyone care to take a shot at it?

Hi David

It's in one of two places. Either at a fitting connection or one of the tubes that fits overtop of the brass lines coming out of the compressor cover. I would suggest that you start by replacing all the fuel lines under the cover and ensuring that they are fully seated in the fittings. Make sure that you cut the ends of the tubing square. If it still leaks, then it is either the fuel or bearing lube line that is leaking, most likely the fuel line. If it is one of these, the you need to replace the lines with either blue or yellow tubing. You can use the clear, but I have best luck with the blue festo line. Since you've already replaced these lines once, you know how tough it is. What I do is cut the tubing to length, put it on an allen key the slightly stretches the tubing and place in HOT water for about 5 minutes. Then I quickly take it off the allen key and push it down on to the tube all the way to the aluminum. The other trick I use is to but a small bead of thick CA at the base of the tube where it goes into the aluminum and push the tubing into to create a seal. You may also want to check the two elbow fitting to make sure that the teeth and seal are not bend out of shape. If they are, then replace the fitting as well.

Good Luck,
Ed

Thanks Ed, I already repalced the yellow tubing with not much luck. My next step si to replace the two 90 deg festo fittings and the festo "Y".

Hi David

The y fitting itself is probably fine. I would just replace the tubing going to and from.

Ed

I will try that Ed. Any difference between using the Blue tube vs 4mm clear tube?

Thanks,

David

Yes, I find that the clear tubing doesn't stay as well and is a little softer than the blue or yellow. I also find the blue is easier to push on because it is stiffer. If you don't believe me, ask my finger tips!

Ed

Ha, I'll take your word for it!

Ed, you da man!

Engine not leaking anymore.

Thank you sir!

David

Hi David,

Back in the shop now. Looks like Ed got you on your way.

Regards.

Hi David !
The next time you will have problem with leaking fuel under the cover, just unwinde the cover put air pressure on the fuel pipe 2,5 - 3,0 bar spray (leakfinder) or similar liquid (soapwater) on all the Festo connection and you'll detect the leak at once.

Happy flying
christer