[EC900]

How long was the storage period? Was there any short 10 minute start ups over winter?
Plenty of temp fluctuations I’ll bet. Moisture affected gasoline could be a culprit.
Gas tank/fuel stabilizer additive used?
How much gas left tank? Drain or syphon and fresh fill up.
I’d try and run the old gas out with an injector cleaner (proper ratio) at a highway speed for at least 50 miles (80k)round trip.