I have a 3820i and want to use a rotary cutter. I have not used the pto yet but notice that the speed on the guage is at around 2500 rpm. Is that too high to keep the engine revved? What gear should I be in. I have been operating, including backhoe, at around 1200 rpm. Please advise as I do not want to blow the engine.
first time use of pto
- Thread starter questadg
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k0ua
Epic Contributor
You wont blow the engine, You say to make 540 RPM on the Rotary cutter the mark on your Tach is at about 2500 engine RPM. that sounds about right for the smaller tractors. The larger tractors will be a little less. It is made to do it all day. Now that said. you do not have to run it that high if you don't want to. You can run it less.. say 1900 or 2000. or so. or even less. BUT. you wont make optimum torque. Your cut results may suffer visually. You may bog down the engine easier. etc.. I sometimes run at a lower rpm when I am in an area that might have a lot of rocks or debris. I don't want to hit as hard as full speed would. Its up to you you wont hurt anything. Just dont "lug" the engine down too much. As for ground speed. choose the one you like and feel comfortable with. If you go too fast the cut results will suffer. as well as the ride on the tractor might be a little bouncy and/or the engine will lug down. Go to slow and it will take longer, the cut will look great, and the ride will be boring
. So to sum up. no real hard and fast rules. experiment, some. but you are not going to hurt it by running at the PTO recommended 540 rpm. If running a hydrostat equipped tractor the ground speed is often varied from second to second as conditions warrant. slower for rough sections and faster for smoother sections of the work. For gear tractor just find a hole you like and go.
James K0UA
. So to sum up. no real hard and fast rules. experiment, some. but you are not going to hurt it by running at the PTO recommended 540 rpm. If running a hydrostat equipped tractor the ground speed is often varied from second to second as conditions warrant. slower for rough sections and faster for smoother sections of the work. For gear tractor just find a hole you like and go.James K0UA
52wej
Gold Member
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- 2004 Century 2535 (3510 Branson equivalent), 2016 Kubota MX 5200
Quest, You will probably find that spending a couple of hours running your cutter at the rated PTO will actually make the engine run smoother. Diesel engines that are run at lower rpm's under light loads will tend to build up deposits that get burned out when they are placed under a heavier and steady load such as that provided by a rotary cutter. As long as you are not lugging the engine it will not hurt it. If you are using the cutter keep the radiator is clean and watch the temp guage to be sure it does not overheat.
I can show you two identical farm tractors, one run under light loads and one used for continuous PTO work. The tractor run under load has noticeably more power, produces less smoke, and starts easier. Have fun. Willie Jones
I can show you two identical farm tractors, one run under light loads and one used for continuous PTO work. The tractor run under load has noticeably more power, produces less smoke, and starts easier. Have fun. Willie Jones
MicroPilot
Veteran Member
2500 RPM is the design spec. Peak torque on the 3 cylinder engines is around 2000 RPM. Running at 2500 allows the engine to fall back into the peak torque range to power through the load. Remember (Torque X RPM)/5252 = HP
MicroPilot
Veteran Member
Depends a lot on the terrain, what you are going to be mowing and your confidence level operating the tractor. If the area to be mowed is fairly level, I'd suggest starting in range 2, gear 1 and see how it goes. If you feel comfortable with that speed, try going up to Range 2 Gear 2.
It will depend SO MUCH on what you use for a cutter and what you are cutting.
"Grass" is easy, although bamboo is a grass (-:
Stalks can be tough.
a 5ft rotary mower takes a lot less power than a 6ft one.
Wet vs dry can make a big difference too.
Try it, see how it goes.
If it doesn't seem to even feel the load try the next higher gear.
Listen to it.
Sure the governor will be doing its job, but you should still have some sense of whether it is taking it easy or just making it.
You will probably find two different gears that work very well mowing up vs down your grades, find one somewhere in between if you are mowing on "rolling" meadows, usually not worth shifting every 50 ft or so.
Black smoke and new smells are usually a bad sign (-:
Cut "quality" does depend on blade speed, not that a rotary cutter is the right tool for "finely manicured lawns", but a slow blade will tend towards tearing instead of cutting.
