mower does not cut very good

[T77911S]

i have a 48in encore zero turn mower. just put new blades on last night. right away it will leave random rows (maybe 2 to 3 in wide) of partially uncut grass. it has done this since I have had it and I am tired of cutting my grass twice.
it seems like the type of grass makes a difference. if it is actual "grass" it cuts it fine. if it is weeds or what I call "highway grass" it seems to have this problem. even if I go slow it does not always cut all the grass. (perhaps a better description of the problem) it does not always cut all the grass. highway grass is the very tall thin grass that has a "Y" at the top.

I usually cut my neighbors grass too but when she cuts mine with her parents cub cadet the grass always looks better. hers does not miss any, but I don't k now what size hers is.

mine is a 3 blade deck and I have heard that 3 blade decks don't cut as but I cant image that being the case or others would have the same problem.

I have about had it with this mower and not cutting all the grass. again, it seems to cut "grass" fine, its when I have weeds that it is worse.

[drkshdw]

Did you sharpen the blades before you put them on? Straight outta the package, they are pretty dull.

We have patches of brome in our yard that our mower won't cut them unless the blades are razor sharp. We get about 3 mows in before the blades do what you describe and a quick sharpen fixes it.

[cabmandone]

First: Cub Cadet mowers, even the cheap ones, do a nice job cutting the grass. Almost as nice as a Simplicity.

Second: My Hustler Super Z will leave a stripe of grass if I mow too fast through taller grass. For me the good news is, my mower mows so fast I can cut it twice and still be done in less time than that Cub Cadet would take to do the lawn once.

I'd suggest checking your deck belt for slippage and make sure your blade spindles spin freely.

[legion]

I had this problem once. Turns out I put a blade on upside down so the back of the blade was hitting the grass.

[unclebilly]

Originally Posted by legion

I had this problem once. Turns out I put a blade on upside down so the back of the blade was hitting the grass.

That my guess.

Also, does one of the blades in a 3 blade setup spin the other direction? Do you have one (two) backwards?

[wswartzwel]

Make sure deck is level front to rear, or approx 1/8" lower in the front (measured at cutting edge of blade not the housing). Park mower on level concrete or paved surface... Engine turned off. Set mower to mowing height, measure at cutting edge of blade to the ground, on left and right sides to ensure it is level left to right. Then rotate blades so they are pointing front to back... Measure again, front cutting edge of blade to the ground. If front is higher or more than a 1/4" lower it will reduce cut quality. Ideal is about 1/8" lower in front. There are adjustments to correct this on most mowers. Some decks have baffles under them to help create updraft and some designs work better than others. Also make sure underside of deck is clean and doesn't have mulch buildup stuck to bottom of the deck. High lift blades will also help.

[asphaltgambler]

^^^^^^^^great post above - just as he said. Only thing that would contribute is a slipping deck drive belt. It could be worn or the tensioner spring has become weak and you'd never know it. Check those and if they look like they've been in use for some time, replace them.

[pete3799]

A loose or worn drive belt will slip on the pulley's when encountering tall grass.

[T77911S]

I rebuilt the deck a few years ago.
all new spindles, pulleys and belts. new springs too.
(powder coated It too along with most of mower).
I have had the mower for several years (bought used) and it has done it since I bought it.
I have put new blades on several times, even the expensive ones.

I cut about 2 acres, I don't have to cut all if it twice, its the "weeds" that give it a hard time.
I went through some nice thick tall grass and it seemed to cut that fine.

you ever seen the highway grass, the stuff that grows really tall really fast and its very skinny and has a "Y" at the top. it will leave a lot of that behind. even going slow.


I will check the deck height but I am pretty sure I set that up after rebuilding the deck.

no, no blades on upside down, always worried I will do that.

I really like and need the Zturn as my yard is not laid out very well. in fact I have NEVER cut it the same way twice. not by choice, it just works out that way.

[peppy]

What speed in the engine running? My zero turn mower requires high rpm for the blade speed and pumps.

[T77911S]

max engine speed.

even tried going slow and it still misses it.

highway grass=Bahia grass.
it cuts the tops but leaves the stalks. looks like the pine tress after a hurricane comes through, the top half of the tree is gone.

[flipper35]

Either dull blades or not enough blade speed. If you are cutting tough stuff you might need to change the angle of the sharpened edge. More boning knife instead of axe but you will have to sharpen more often.

I put Gators on to replace the OEM on my Cub with the 3 blade 50" deck. They cut much better than OEM and were less expensive. I still have to go slow on the ditch with ragweed and stuff.

[T77911S]

i have used the gators too.
no better.
brand new blades last night. they were pretty sharp.

I have tried different cutting heights thinking that with the deck too hi the grass is easy to get "pushed" over vz the blade hitting the grass down low, no difference.

it was better with the new blades, but still nothing like the cub cadet, very aggravating to see the CC outcut my ZT.

[wswartzwel]

Does your mower have baffles near the blades to help create air flow?

[LEAKYSEALS951]

^that was my guess. I've got a swisher 66 deck as a side pull finishing cut mower and it's just a big piece of metal with blades on it. There is no baffling under it to keep air flowing, and the cutting quality if lower. I end up re-going over it with the JD deck to fix the swisher bad cut.

[rusnak]

A picture of the grass would help.

If your lawn is more like a field of tough weeds, then you might need a flail mower driven by a PTO with a real tractor. Otherwise, it does sound like your weeds are clumping and balling up inside the mower deck and not being cut by the blades.

[wdfifteen]

I would guess blade speed is the problem, probably a slipping belt.
In my experience weeds are easier to cut than grass. The stems are more stiff and stand up longer. Grass gets blown around by the air under and in front of the deck instead of standing up straight.

Off topic, but I’ve noticed my new Grasshopper cuts great going forward, but doesn’t cut worth a damn moving backwards. Something to do with deck design I guess.

[cstreit]

My guess is the airflow inside the deck. I had a similar issue and switched to something called like "Gator Blades" which are designed for mulching instead of general purpose, much more even cut since then.

[rusnak]

Or the lawn is just wet

[Crowbob]

I'm going with the culprit being a bad spindle bearing.