I have a previous generation eXmark Lazer Z with the 28HP Kawasaki FH770D KAI. Over the last month (I only use it about 1 per week) I've noticed that under a heavy load, such as stopping on a hill with the blades engaged and then starting to go up the hill again, the engine will sputter a little. It seems to be getting a little worse now and to me it sort of sounds like it's starving for fuel. It runs great otherwise and only has less than 100 hours on it. I put a new fuel filter on early this year as part of normal maintenance. So when I looked down at the fuel filter to see how much gas was in it while the engine was running full speed with the blades engaged, I was surprised to see only a small puddle of fuel at the bottom of the filter. I would have thought it would be mostly full. The question is, how full should that fuel filter be when you look at it with the engine running full speed? Maybe the fuel pump is going bad? Though it has less than 100 hours on it, this mower was a leftover and sat unsold for close to 3 years before I bought it. Not sure if that has any affect on the fuel pump condition. My idea was to go the easy route and replace the fuel pump to see if that's the problem. Make sense? Is it abnormal for that fuel filter to only have a small pool of fuel at the bottom??? I would have thought it should be at least half full or more if the pump was working well.