I've noticed this year on my 430 with my 50" single stage blower the tractor has to go very slow when taking on the full width of the blower in snow. This is in various snow conditions light and fluffy or heavy and wet. Last year I thought it didn't struggle at all taking on any type of snow at full width, or maybe my memory isn't as good as it used to! It's very easy to take on too much snow and have the engine die. When it does start to struggle the rpms drop and there is black smoke. I'm using low gear on the 2 speed transaxle as I was last year. It will still throw the snow okay as long as I go extremely slow or take on half width. I have replaced all filters and fluids on this tractor except for the fuel filter. I have a new fuel filter to install, but this doesn't make sense to me that the fuel filter being plugged would cause black smoke. Any thoughts appreciated.