How can i fix my Ryobi 40cc 16 inch chainsawbar lubrication?

My brother in law borrowed my chainsaw and ran it with out chain lubrication oil, resulting in a scorched bar. After filling up the chain oil reservoir, it no longer lubricates the chain. There are no blockages I can see. I managed to push what looked like a metering pin in with a screwdriver which resulted in a bit of lubrication for a short while only. Help please!!