Fuel lines to carburetor - stainless vs teflon

Thanks all. I haven't been able to find a service bulletin that required replacing the SS lines. Is that an official thing from Rotax or more of a best practice?

Best practice.

So long as you don't put too much pressure on them by bending they should last.

Hi all

The certified engines with the Rotax distribution block, both 912 and 914, used stainless fuel lines to comply with the TSO requirement for fire safety.  (must withstand 2000 F for 5 mins) 

The TSO lines today are special material coating over a teflon inner line with the same spec on temperature and time.  There is nothing wrong with the stainless lines, some being in service for over 25 years now. 

Cheers

Roger L & RW,

How can a ridgid (steel) fuel line to carb, not interfere with the vibration damping of the rubber inlet manifold????😈

Hi Sean

The certified lines were always ridgid stainless up until they switched to the soft lines on the non-turbo engines many years ago.  The type 914 is still rigid line even now from the distribution block to carbs and regulator.  

The shape of the lines is not straight, it curves and the design allows for the amount of movement within the assembly.  The airbox, used in all certified applications, has a lot of influence in keeping the whole system together and minimizes movements that might allow one to move out of harmony of the other.  In the decades I have worked with them we never see fuel line leaks or cracking of the stainless under normal operation.  The rubber connectors are more to damp the high frequency vibration and also isolate some heat transfer from the manifolds.  Under normal clamping with the airbox there is very little independent movement.

Cheers