First, you need to know if your 441 is computer controlled or has an adjustable carb. They made them both ways. Look on your recoil. If it says MS-441 you have an adjustable carb. If it says MS-441C it has a computer, and you should never have to adjust it.
Secondly, if a saw does not run right after you loaned it out, I would not blame the saw.
Third, the 400 is a good saw, but it is not the replacement for the 441. A 462 is the same cc-s and is lighter and will outrun the 441. In addition, you can get the model with the computer (462C) and you will never have to tune it.
460s are good saws, but they all had adjustable carbs.
As they made saws more emissions compliant, the range they would operate w/o adjustment narrowed.