i hav a hustler tht i had the engine replaced a couple of months ago. i noticed right away that it did not have as much ground speed as before. i figured it might be turning a few less rpms in the engine. the mechanic told me he had lowered the rpms a little. did not notice any real problems. then i put the bagger on for leaves last week and now it dose fine on the flat or going up the drive but i hit the slightest hill and it dose not want to go.