Belly mower does a ragged job - why?

[sunandsand]

Got a belly mower on my Kubota 2601. I have 160 hours or so on the tractor, maybe 60 or 70 (tops) of them mowing with the belly mower. (The tractor gets used for other things, too.)

The mower cuts grass poorly, leaves streaks, cuts unevenly, leaves stubble of various lengths, just does an ugly job. I don't expect it to manicure the grass, but I think it should be doing a better job than it is. I have a (crappy) garden tractor that does a much cleaner job (when it runs, but that's another story).

The area is pretty flat, no rocks or gravel, the grass is cut fairly frequently, so I'm not asking it to cut down the Amazon rain forest. I've set the anti-scalp rollers according to the manual, and the cut height is usually set between 2 3/4" and 3.5".

I do know the back of the mower deck should be slightly higher than the front, and I know how to adjust it. I can park the tractor on a level concrete floor to make any adjustments. Mowing speed doesn't seem to make any difference, if I am in high range, I just get a crummy job faster than if I am in low range. Throttle is usually set about 2100 rpm, redline is 2600, the grass looks the same but the tractor just makes more noise and burns more fuel.

I'm open to suggestions . . .

Best Regards,

Mike/Florida

(The larger the island of knowledge, the longer the shoreline of ignorance.)

 

[SgtSluggo]

Two things come to mind that have affected other mowers that I have used. I would check the blades. They might not be dull, but it doesn't take a lot of damage to make them leave a less than ideal cut. It's also possible that if you have ever cut even slightly damp grass that you might have some buildup on the walls of the mower deck. Scraping that off can improve cut too.

 

[4570Man]

Are your blades on upside down? Are they reasonably sharp and the bottom side of the deck pretty clean? A belly mower should do a pretty good job. Something is definitely going on.

 

[Rdrcr]

My B2601 (w/60” MMM)
did a pretty darn good job mowing my property. I mowed in Medium gear at roughly 2,300 RPM without the loader attached. Quality of cut was good, not as good as my new ZTR, but good.

Mike

 

[TMGT]

What kind of grass are you cutting? I know some of the warm season grass down your way can be pretty tough cutting.

I'd go over everything mechanical, make sure blades/belt are sharp and not slipping, underside of deck is clean and deck is properly adjusted per the manual as some decks require either the front or rear to be lower.

Finally get your rpms up, the rated pto speed is at approx 2800rpm for the mid pto (2753 to be axact), running your blades to slow won't create enough lift to pick the grass blades up on some species preventing them from being cut evenly and will just kind of beat them rather then cut. Mid range is good for ground speedfor ground speed, high will most likely be too fast for a good cut.

 

[Midniteoyl]

Are your blades on upside down?

This was my first thought as well.

 

[big bubba]

existing blades probably dull & bent. bent blades are often overlooked for a poor cut. bite the bullet, get a new set. use blocks & impact to replace them

 

[LD1]

Take a picture of the underside of the deck.

Check everything out mechanically. Spin the blades where two of them almost touch.....are they at the same level? spin one of the blades 180....still the same.....now spin the other....still the same? repeat for the third spindle.

Deck buildup as mentioned? Deck has to be clean for proper airflow and cut quality. Are the blades the right length? Does the mower have an adjustable baffle?

Not saying its your case....but alot of people that have CUT's or SCUT's with belly mowers never take the mower off when doing other things with the tractor. I have seen bent blades, spindles, decks, etc just from leaving the deck on and doing work in the "woods" and driving over sticks, rocks, stumps, etc. So look everything over for physical damage.

And do you have any pictures of what the cut looks like after you are done? You are cutting it ~3" high but how tall is the grass that you are cutting? IF you are trying to cut 10" tall grass down to 3" and only mow every 2-3 weeks you will have bad cut quality too.

 

[sandman2234]

I think the grass in Florida is just getting harder to cut! Absolutely cannot be the tractors fault! However to address the harder to cut Florida grasses, I would look into making sure the belt is transferring the power, and that the blades are sharp. Adjust the belt, or better yet, replace it with a very good quality belt. Save the old belt as a spare, in case the replacement doesn't make any difference. Double check the blades, or resharpen them, or replace if that is your normal choice. My JD2555 pulls a 5 foot finish mower at times, simply because I have it, and if the blades aren't sharp and the belt is slightly loose, it requires me to drop 1 or 2 gears while mowing to keep the cut pretty. Considering it is a 70 Hp tractor, it isn't a hp shortage, just getting the hp to the grass.
David from jax

 

[4570Man]

What you are expecting the MMM to do is another good point. It’s not a bushhog. Using it as one will lead to disappointment.

 

[sandman2234]

What you are expecting the MMM to do is another good point. It’s not a bushhog. Using it as one will lead to disappointment.

And to it not cutting grass as well after trying to use it as a bushhog!
David from jax

 

[CH4Ohio]

Every mower I've ever had except for REAR PTO driven mowers has been run at WIDE OPEN THROTTLE.

Push mowers, cheap riding mowers, tractors with belly mowers -- always run wide open.

Does anyone have a push mower that they don't run at WOT? Why would a belly mower be any different?

My RC72-27B (72") mower cuts really slick running at WOT. It would do a lousy / ragged job at 2100 RPMs.

 

[hube2]

Every mower I've ever had except for REAR PTO driven mowers has been run at WIDE OPEN THROTTLE.

Push mowers, cheap riding mowers, tractors with belly mowers -- always run wide open.

Does anyone have a push mower that they don't run at WOT? Why would a belly mower be any different?

My RC72-27B (72") mower cuts really slick running at WOT. It would do a lousy / ragged job at 2100 RPMs.

I don't go WOT, don't like the sound of my tractor there, but I do run it at the top of the green area on my tach while under load. It does not do as nice of a job running I run my 540 PTO blower the same way.

My FIL was complaining to me about the way the old tractor I gave him was cutting, said he needed new blades. It had a brand new set of gator blades on it when I gave it to him. Asked him if he was running at at full throttle and he said no and I explained, but he still refuses to open it up and instead keep telling me what a bad job of mowing it does.

Running it slower can actually cause blades to dull quicker as well and allow more debris to build up under the deck.

Not saying that this is the OP's problem at all, just saying that it can be a contributing factor.

 

[nyone]

Poor cut or leaving strips uncut is telling me your either driving to fast or your decks blade tip speed is slow.

Becids the obvious dull blades and I hope your mowing near max rpm.

Blade tip speed is one very key thing needed when mowing that's also left out of manufacturers specs.

 

[CH4Ohio]

Had to go look at my tach. On my tractor, I need to be running at 2600 RPMs in order to be at optimum PTO speed. As mentioned, I usually mow at WOT and that would have me about 200 RPMs above the mark indicated on the tach.

My tractor runs and sounds good at that speed.

No way could I get good results mowing at 2100 RPM as was mentioned in the original posting. That's on my tractor.

 

[CH4Ohio]

Not to beat a dead horse here, but . . .

Are we talking about a B2601 tractor? Does the dash and tach look like this? The operators' manual that I just looked at shows the PTO hash mark on the tach at 2800 RPM.

I'm not clear where the info about it redlining at 2600 came from, but looks to me like it's being run way too slow to cut grass. Simple fix.

 

[marhar]

Are your blades on upside down? Are they reasonably sharp and the bottom side of the deck pretty clean? A belly mower should do a pretty good job. Something is definitely going on.

I bet you have the answer...upside down or backwards.

As a side note I had a friend put a chainsaw blade on backwards....the results were as expected. Every time he had a blade go dull we joked with him and asked what direction the blade was in.

 

[Slowpoke Slim]

I bet you have the answer...upside down or backwards.

As a side note I had a friend put a chainsaw blade on backwards....the results were as expected. Every time he had a blade go dull we joked with him and asked what direction the blade was in.

I can visualize putting the mower blades on upside down by mistake, but how do you put one on backwards?

Wouldn't it either be "right side up", or "upside down"?

 

[marhar]

I can visualize putting the mower blades on upside down by mistake, but how do you put one on backwards?

Wouldn't it either be "right side up", or "upside down"?

You are correct. I was thinking of a single spindle rotary mower that has one side that cuts and the other side that does not. A belly mower blade is more like a push mower in that both sides cut, correct?

 

[zzvyb6]

If you put a chainsaw blade on backwards, you have 2 choices: Run the motor backwards (takes a different recoil setup), or leave the motor off (save the environment) and use it like a handsaw. If you are REALLY handy, you can change it back to normal without shutting the motor off (in case of hard starting machines). Either way, "Life is Tough, and tougher if you are ...".