Stihl ms251 fuel tank housing and ms251c

[river.sawyer]

I need to replace a fuel tank housing on a ms251c that has a primer/fuel return line going to the tank. The ms251 housing I have does not have a fuel return line, though the place where one would get plugged into the fuel tank housing is there. Would it be possible/advisable to drill a hole into the tank and add a fuel return line?

 

[Kaimana]

Your language is confusing; I can't tell which is your spare part and which is your saw.
Does your saw have a fuel tank housing with a primer/fuel return line going to the tank? Then get a new one of those, don't try to install something with no fuel return line.
Or does your saw have NO fuel return line? If so, get a new one of those, don't try to install a tank that has a fuel return line.
Unless you're the chainsaw god, get the right parts for your saw, don't try to make something else work.