Where did you get that ratio? my 75 Gareli asks for 25:1
second question. You say it's oil injected and you still mix fuel????
if it has real oil injection it would have a separate tank just for 2 stroke oil And there would be no need for you to mix.
My concern is that if you don't have injection (and I am not certain any Garelli did) that by running 50 to one you were dangerously low on lubrication and by added another 1/4 gallon of gas you've kicked it up to something like 70:1
Wait for other answers .. I could be wrong on the injection thing, but I'd want to dump that fuel out if it were in my Eureka flex. (Ok, dumping gas is tricky, I'd prolly run it through my older car that doesn't have a cat convertor on it) Start over with a Fresh tank of 25:1 your bearings and rings will love you for it.