5 YEAR RUBBER REPLACMENT

Different owners and aircraft Mfg's use either rubber or silicone. Without seeing them it would be hard to know what you have. You should replace all rubber fuel, coolant and oil hoses. If they are silicone it's "on condition" Typically the rubber hoses are black and the silicone are colored,, i.e. blue, orangish or red. Even if you have silicone hoses do a good inspection and make sure nothing is rubbing through or too near an exhaust pipe and getting damaged.

Plus you have other parts like the rubber carb sockets and their "O" ring, the rubber sleeves on the carb balance tube, carb diaphragm's, rubber engine mounts, the rubber 17mm coolant hoses on top of the engine and under each set of cylinder's, ect.... 

Hi Micha

The maintenance manual line, MML, shows what parts are needed.  In addition in the text callout they tell you the standard practice to inspect the hoses.  

Anything you purchased on the engine that would have been an option, such as silicone hoses, will be shown in the configuration of your engine.  This can be viewed online at the flyrotax.com web page, you will need your engine serial number.  There are indeed 2 part numbers for most of the cooling hoses and in general all the black ones on your engine are not silicone.  Rotax has used a blue and in some cases a dark red/brown silicone type hose.  If you are in doubt have an aviation technician look at your engine, they should be able to tell you if you are not sure.  

Cheers

Here is some information from a hose supplier this suggests dont just grab any silicone hose, be sure it is right for the applicaiton.    This is in a Q&A at their website on hoses. 

https://www.siliconehose.com/

"Are there cases when silicone hoses aren’t ideal?"

"Yes! Although silicone hoses are ideal in ALMOST every situation, there are certain cases where it’s not the best choice. Silicone is permeable to fuel and oil, so we don’t recommend that you use it for any application where the hose may come into contact with fuel or oil. And, while silicone is watertight, it is still permeable to water molecules, which can escape slowly through the walls of a silicone hose. For this reason, silicone hoses are more ideal in automotive applications in race cars and performance vehicles rather than in a vehicle you’re using as your daily driver."

food for thought.

Cheers

Here is some information from a hose supplier this suggests dont just grab any silicone hose, be sure it is right for the application.    This is in a Q&A at their website on hoses. 

https://www.siliconehose.com/

"Are there cases when silicone hoses aren’t ideal?"

"Yes! Although silicone hoses are ideal in ALMOST every situation, there are certain cases where it’s not the best choice. Silicone is permeable to fuel and oil, so we don’t recommend that you use it for any application where the hose may come into contact with fuel or oil. And, while silicone is watertight, it is still permeable to water molecules, which can escape slowly through the walls of a silicone hose. For this reason, silicone hoses are more ideal in automotive applications in race cars and performance vehicles rather than in a vehicle you’re using as your daily driver."

food for thought.

Cheers