Belly mower does a ragged job - why?

[KennyG]

I have an JD X300 and the owners manual says to run the engine at full throttle when engaging the blades. And that’s what I do, I push the throttle wide open and engage the blades and start mowing. Also, according to my small engine repair guy, he told me that a lot of mowers will get too hot if the rpms are too low for too long cause the engine is not getting enough air.

I think it means to run at full throttle AFTER you engage the blades. If you go full throttle before engaging the blades, I predict a short life for your blade clutch. Engage the blades at idle and then go full throttle.

 

[ed1978]

the turned up portion of the blades is worn....it will not create a good vaccum. replace them....you will hear the difference immediatly.

 

[Midniteoyl]

I think it means to run at full throttle AFTER you engage the blades. If you go full throttle before engaging the blades, I predict a short life for your blade clutch. Engage the blades at idle and then go full throttle.

Several of us, me included, have mowers whose manuals specifically say to engage at full throttle.

 

[stuckmotor]

My riding mower didn't cut worth shucks for years. I finally tightened the belt and solved the problem.

 

[CH4Ohio]

This entire thread reminds me of another over-engineering story.

NASA in the 60's was under the gun to put a man on the moon. A subset of engineers was charged with developing an ink pen that would write in zero-gravity. Our astronauts had to be able to complete their checklists and make notations and needed a reliable writing instrument.

After months of research and prototypes they partnered with a manufacturer to produce pressurized ink cartridges that worked in space. These pens were also marketed here on Terra Firma because they would write upside-down, etc. (By Papermate, maybe??) We spent millions of dollars and lots of brainpower to overcome this tremendous problem.

The Russians just used a pencil.

 

[dogrv]

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.)

Run it wide open for best performance

 

[Sonny580]

Dont drive so fast!!! --- THAT is the major problem with most guys--- ya cant mow at 10mph!!
I use an old sunstar 20 and never get out of low range in the hydro. -- Takes a long time but it moes great,---- same with my 185 lo-boy and creeper gear----- get going too fast and ya it quits cuttin and just fans the grass! lol!
Try running slower just for the heck of it!

 

[JWR]

Several of us, me included, have mowers whose manuals specifically say to engage at full throttle.

Several of us are reading directions written by people with poor English skills and not involved in the logic of what they are saying. It is 100% obvious that you can minimize the wear/tear/jerk by engaging the mower at a low rpm before revving it up. Duh ! The manual saying to "engage" at full throttle needs to be rewritten to say "operate at full throttle" not "engage at full thorttle."

 

[JWR]

I'll let the sharpener guy look at them in the next day or so. If I need new blades, I'll get them. No biggie.

I did look at the parts book for the RCK54 mower - there doesn't appear to be the right side guide plate/baffle plate as on the left side. I'll check with the dealer Tuesday.

Best Regards,

Mike/Florida

Your Plan post just before this one is a good one. I suspect you may have a missing or bent set of baffles (on your list) and may need new or sharpened blades. MMM are notoriously touchy for best setup in terms of scalping height adjustyment, angles, etc. If your baffles are good and your blades are good and your rpms are full rated rpms, it will cut smooth and mostly free of standing scraps.

 

[CH4Ohio]

Not a true story: Fact or Fiction?: NASA Spent Millions to Develop a Pen that Would Write in Space, whereas the Soviet Cosmonauts Used a Pencil

If fact it's believed that the graphite is what sparked the fire that killed Grissom and crew.

Oh well. It was kinda offered as a "parable" anyway. I'm not surprised that it didn't pass the fact-check.

Regardless, don't you think that a lot of this discussion has missed the smoking gun comment that he's mowing at 2100 RPM??

 

[Midniteoyl]

Several of us are reading directions written by people with poor English skills and not involved in the logic of what they are saying. It is 100% obvious that you can minimize the wear/tear/jerk by engaging the mower at a low rpm before revving it up. Duh ! The manual saying to "engage" at full throttle needs to be rewritten to say "operate at full throttle" not "engage at full thorttle."

Owned by, designed by, and built by a company in Albany, In. No translation problems I would think.

I get the reasoning, just saying that not all manuals state the 50% throttle position.

 

[Midniteoyl]

Regardless, don't you think that a lot of this discussion has missed the smoking gun comment that he's mowing at 2100 RPM??

It did at first but there have been lots of posts regarding it since he mentioned what it was suppose to be. I just assumed when he said 'at 2100rpm' in his first post that he was talking about deck/blade rpm. Once he cleared that up it became kinds obvious he was running too slow.

 

[sunandsand]

Blades going out tomorrow for sharpening, and a new set will also be ordered (just in case). All baffles appear to be present, unbent and accounted for (no RH baffle according to the parts book). Belt good, not slipping, not cracked or glazed.

When it is all put back together, I'll take it out and run it harder. I also intend to double check the alignment, angle and the height of the anti-scalp wheels.

This ought to be done by this coming weekend, and I will advise my results.

(The problem with the Russian pencil trick was conductive graphite flakes floating around in zero-g. The Apollo fire was caused by a spark in an almost pure oxygen atmosphere, which was kinda dumb because the astronauts had their own air supply anyway - so there was no real reason for having a pure O2 atmosphere in the capsule itself.)

Best Regards,

Mike/Florida

 

[CH4Ohio]

Blades going out tomorrow for sharpening, and a new set will also be ordered (just in case). All baffles appear to be present, unbent and accounted for (no RH baffle according to the parts book). Belt good, not slipping, not cracked or glazed.

When it is all put back together, I'll take it out and run it harder. I also intend to double check the alignment, angle and the height of the anti-scalp wheels.

This ought to be done by this coming weekend, and I will advise my results.

(The problem with the Russian pencil trick was conductive graphite flakes floating around in zero-g. The Apollo fire was caused by a spark in an almost pure oxygen atmosphere, which was kinda dumb because the astronauts had their own air supply anyway - so there was no real reason for having a pure O2 atmosphere in the capsule itself.)

Best Regards,

Mike/Florida

Great! Let us know how it works when you get a chance to run it. Still mowing a LOT here -- usually it's slowed down by this time of the summer.

 

[ljjhouser]

Its a mindset I dont think you are ever gonna change. Its laughable to think one buys a tractor and should keep it under 25% service factor...lol

T4 might help with that mind set. Run it hot or have to regen often. That might convince someone to operate at high power. By the way, on my tractor, 2800 is full power and 540 pto.

 

[sunandsand]

Running at less than full power to save the engine . . .

Not just limited to tractor operators.

The small Continental aircraft engines (C-75, 85, 90 and O-200) last longest when they are FLOGGED. Pilots who "baby" the engines usually don't make it to the normal 1800 hour overhaul interval. The ones that do are usually in trainers (like Cessna 150s) and get mercilessly abused by student pilots day in and day out, but they run happily to TBO (time between overhaul in hours) or beyond.

Go figure . . .

Best Regards,

Mike/Florida

 

[4570Man]

Oh well. It was kinda offered as a "parable" anyway. I'm not surprised that it didn't pass the fact-check.

Regardless, don't you think that a lot of this discussion has missed the smoking gun comment that he's mowing at 2100 RPM??

Mowing at 2100 rpm and with blades dull as a banana are definitely contributing factors. That definitely needs addressed before further trouble shooting is done.

 

[LD1]

This ought to be done by this coming weekend, and I will advise my results.

You never did answer (or maybe I missed it) how tall are you letting the grass get, and how close are you trying to mow it, and how slow/fast are you going?

you started this post 5 days ago. Mower still isnt fixed and now you are hoping it will be done by this weekend to try out.

Maybe you have had some weather that the grass is kinda stagnant and not growing fast. But up here....a week in between mows is almost too long....and you have to slow down to get a quality cut even with a professional zero-turn. And you are going LONGER than that between mows with a belly mower. Perhaps just mowing more frequently would solve the issue.

Quite simply no matter what kind of mower you have, you cannot let it get to 8", then try and cut it back to 3", and have a nice healthy lawn and clean manicured looking cut.

As the saying goes.....your never supposed to cut off more than 1/3 of the grass at a time. So if you want your lawn at 3"....you need to be mowing when its only 4.5" tall. If you want it 4, dont let it get over 6. And in times of fast growth....yes this means mowing a couple times a week. If you only want to mow once ever 10-14 days.....worrying about quality of cut and the looks of your lawn is pointless.

Maybe none of this applies in florida? So maybe Im barking up the wrong tree. But thats how it is here in the midwest.

 

[Williy]

I believe you don't have the PTO set for 540 rpms
and going too fast remember hast makes waste!
The grass could be too high, thick etc.

willy