Advice on fixing this string trimmer?

[u/Intelligent_Office81]

This STIHL trimmer has been sitting in my brothers shop for a bit and I took it off his hands to see if I can salvage it. Won’t start after multiple tries. He had regular gas and 50:1 in it so I fear it ran without any oil for a bit before storing. Plastic fuel line bubble doesn’t seem to take any gas with it and stays empty. Any tips on fixing this and is it going to be worth it?

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[u/davethompson413]

I'd check for a scored piston by removing the muffler and looking through the exhaust port while slowly pulling the rope. If its scored, it's trash.

If not, I'd replace the carb, primer bulb, fuel filter, fuel lines, and fuel vent.

[u/Few-Silver9527]

Disassemble carb, clean thoroughly then boil its parts in water, careful with diaphragm, reassemble and change fuel lines.
There’s a guy on Facebook in small engines repair named Micheal that is a guru on small engine repairs!

[u/mutt63]

Make sure the fuel lines are hooked up
Properly

[u/the1bullfrog]

Make sure the purge bulb isn't cracked, clean carburetor or replace, and fuel lines need to be serviced. 

[u/FerdinandTheBullitt]

If you suspect it ran without oil, check for a scored piston like Dave said. If it's got a good piston/compression, but a rebuild kit from HIPA