deck not cutting properly after sharpening blades

[Markcuda]

Like I said, mine does it ever so slightly, but I can see it, at times, not all the time either.
It has me stumped

 

[beenthere]

I would suspect the belt before the sharpness of the blades (assuming you know how to sharpen them ).

Also check the belt and the center spindle for excessive heat after running for a half hour or so. If the spindle bearing is bad, then there will be heat there. If the belt is slipping on the center pulley, the belt will/should be warm.

Also, be sure the deck is leveled properly and that the mower deck is being carried, and not running on the ground. That front roller may be pushing the grass over and the blades can't lift it soon enough to cut it.

 

[tmajor]

I had one 3 blade deck that didn't work as it should. I found that the idler pulley, which is spring loaded, had frozen on the pivot shaft. As result, in some instances, the belt would not have the proper tension. So, make sure the idler pulley is free to move on the pivot and that the spring works.

 

[jinman]

I've never seen a 5" swath go uncut, but certainly I've seen many times that worn blades leave a couple of 1" uncut trails even when the blades are very sharp. The overlap on a 48" is provided by three 17" blades so that the total overlap is 1" between the center and outer blades (1/2" over lap by each blade = 1" total blade-to-blade) If somebody put three 16" blades on your mower instead of full 17" blades, that could be the problem. Since blade tip speed is much higher than toward the center of the blade, the tips wear very quickly. I would get one set of special high-lift blades from John Deere and see if that didn't help. Airflow and blade lenth are the two critical factors for multi-blade performance in my opinion. I only sharpen my blades once and then toss them because the sand in my area erodes the lift fin at the back of the blade so badly that they become paper thin and sometimes have eroded completely away. I also think that the angle of the deck and type/length of the grass has a lot to do with condition of cut. My lush St. Augustine grass cuts much better than bermuda and far better than weedy grass.

 

[meb9796]

Now I'm really stumped!! I took the blades in to get them sharpened, put them back on, greased up the deck 'again' made sure all the pulleys were turning properly, and replaces the belt, and I still got the 5" path of uncut grass, regardless of speed (crawled and went as fast as I could go with the same results. I have a large front yard with thin grass in some sections and real thick grass in the middle, it the did the same for the entire yard, regardless of type of grass or speed.

I took the deck off 1/2 way thru cutting the yard (was a bit peeved at this point) and checked the entire thing again, and even swapped the center blade with one of the side blades and STILL got the 5" strip.

I still think it has to do with belt tension because the two end pulleys have more contact (i.e. friction) with the belt and the middle pulley has about 1/2 the amount of contact, so seems liable for it to go first if the tension is off. Since I replaced the belt, what about the spring that is on the deck? Should that come off easily?? It takes almost no effort for me to remove/replace it. I think I'm going to stop by the JD dealer and ask to see one of the springs to compare the tension and possibly try new blades, even though I really doubt that is it. While I'm at it, I might as well get a new belt for the mower to the deck too, I did notice a few cracks in that while I was taking the deck off this afternoon.

Thanks again for all the input and I'll keep you posted.

 

[tmajor]

As I said before, "the idler pulley" needs to move back and forth (on it's pivot) easily, with the spring tension against it. If it's frozen on the pivot, the spring does absolutely no good.

 

[High Compression]

I bought my wife a GT245 mower about a year ago (used) and just noticed that when she's cutting the grass, it leaves about a 5" section in the middle un-cut?? It's a 48C deck and I just sharpened the blades and cleaned out the deck of old grass, greased up the entire mower and it's still doing it.

Could it be the belts are slipping and not turning the blades as fast as they should be, or is this from dull blades? After I sharpened the blades, I mowed the grass very slowly and it still left the 5" section in the middle un-cut.

any suggestions??????

thanks

On my Kubota ZD21, the blades have to be indexed in the right positions for it to cut properly. I never saw this before until I read my manual. Maybe worth looking into.

 

[tawilson]

Have you got off it while mowing to pinpoint the 5" strip? It couldn't be a antiscalp roller flattening the grass?

 

[Dutch445]

Have you got off it while mowing to pinpoint the 5" strip? It couldn't be a antiscalp roller flattening the grass?

not a bad thought.

there was mention you didn't feel the deck had the same
power as when you first got it, any chance engine rpm's have
fallen out of spec? combine that with the rolled over grass from
the front antiscalp roller, and maybe the slower deck speed
isn't creating enough vaccuum to pick that grass back up?

i would imagine that spring has quite a bit of tension to it
once the belt is on. any chance the belt is not the right belt?
any chance you got a belt from an older 48 deck instead of the
newer 48C? worth verifying.

 

[kthompson]

Don't know your deck but for "A" patch not to be cut does not make sense on a three blade cutter to me. If it was the blade being worn or such would seem have to be a issues on both sides of the center blade if any issue with the center blade or it not turning. The thought it is a wheel or roller makes the most sense. As another pointed out be sure you are running the full rpm for the mower.