Asymmetric throwing distance

I've got an 11 y/o YS-624, and I have noticed for a number of years that it throws noticeably farther when the chute is pointed toward the right or straight ahead compared to the left.
This leads me to have to go in a particular direction in my driveway when the berms get too high - a little annoying perhaps when I'm trying to stay ahead of dumps of several feet at a time here in northern Norway (Tromsø).
Also, is there anything that I can coat my chute to keep moist snow from sticking (it's a little pitted on the inside from years of gravel from my driveway early in the season).
Thanks for any insight.