Can premix damage fuel line anyhow?
 

Can it damage fuel line or some meter gauge in long term anyhow? Like gasoline looked cleaner than 2 cycles..

No..... :-)

Waylon; I urge you to stop posting and start using the search function more often. Many of the questions you are asking have been answered and discussed many times. In just one day you have posted at least 3 threads all of which have been answered in other threads. If you need help searching

Please check out this thread for the most commonly asked questions, as well as some detail on how to search:

https://www.rx8club.com/new-member-f...t-here-202454/

To answer your question:
No it cannot damage fuel lines or the fuel gauge.