What is the purpose of the small Black rubber line on starboard side Merc 80hp

[MyName]

Can someone identify the purpose for the small black rubber 7/64" vacuum/other type line coming down about 1 foot+ on the starboard right side of the Mercury 800 80 hp 1978 two stroke oil/gas mix engine Ser #005009751

 

[racerone]

It is an oil recirculation line.-----Perhaps talk to your local friendly repair shop.