This is my first post to a site I had not heard of till an email from Tractorbynet letting folks know you exist. I'm happy to be part of the community and I'm happy the forum is here. Not sure why I was surprised actually, there are forums for EVERYTHING. 
So on to my question. I have a Honda HRX217TDA that I bought new in 2004. It still runs very strong but does have a bit of oil smoke about every 3-5 starts. Everything works fine and I have a second set of blades I change out 1-2 times a season which brings me to my question. I have noticed the last few years, it seems to be missing a lot of grass, and not like you'd think. I can walk one swipe and on my way back the other way, I see large sections about 5-6" across that appear to just be laid down by something, the area around is cut, then these little areas stand back up and are clearly not cut. Sometimes those areas are smaller like 1-2" or even a single blade, just...missed in the middle of cut grass. Small areas and one blade I could see, but the larger areas make no sense to me. I have wondered about the deck not having the vacuum affect, if that's even a thing, like it used to and not picking up the blades, or maybe something on the mower is holding the sections down and not cutting it? Also, I notice as it regrows, I can see clear lines of taller grass that would be the width of the deck. I have tried lining up the center of the deck with the cut line and just mowing half the deck width, with no change. I have also wondered about the type of grass I have maybe laying down on its own, then the deck sucking it up after it has passed by and cut. I do see a lot of areas where the grass is long and doesn't really get cut a lot because it's laying flat on the ground. I can rake those areas up with a lawn rake then mow them.
I do mow at the highest setting too, which kind of made me wonder if the height is just too high to cut it efficiently.
The grass I mow now is a mix of Kentucky Bluegrass and Fescue. The lawns I had before were St Augstine and Bermuda. I did not see this cutting effect then, which was in 2004. Just recently.
Any thoughts would be very helpful I'm sure.
Thanks
So on to my question. I have a Honda HRX217TDA that I bought new in 2004. It still runs very strong but does have a bit of oil smoke about every 3-5 starts. Everything works fine and I have a second set of blades I change out 1-2 times a season which brings me to my question. I have noticed the last few years, it seems to be missing a lot of grass, and not like you'd think. I can walk one swipe and on my way back the other way, I see large sections about 5-6" across that appear to just be laid down by something, the area around is cut, then these little areas stand back up and are clearly not cut. Sometimes those areas are smaller like 1-2" or even a single blade, just...missed in the middle of cut grass. Small areas and one blade I could see, but the larger areas make no sense to me. I have wondered about the deck not having the vacuum affect, if that's even a thing, like it used to and not picking up the blades, or maybe something on the mower is holding the sections down and not cutting it? Also, I notice as it regrows, I can see clear lines of taller grass that would be the width of the deck. I have tried lining up the center of the deck with the cut line and just mowing half the deck width, with no change. I have also wondered about the type of grass I have maybe laying down on its own, then the deck sucking it up after it has passed by and cut. I do see a lot of areas where the grass is long and doesn't really get cut a lot because it's laying flat on the ground. I can rake those areas up with a lawn rake then mow them.
I do mow at the highest setting too, which kind of made me wonder if the height is just too high to cut it efficiently.
The grass I mow now is a mix of Kentucky Bluegrass and Fescue. The lawns I had before were St Augstine and Bermuda. I did not see this cutting effect then, which was in 2004. Just recently.
Any thoughts would be very helpful I'm sure.
Thanks