Drum Mower with 25hp Tractor

[Brownac71]

I've got a Kioti CK2610 that I use to cut and make hay on about 5 acres. Been making hay for 3 years now using an 80 year old sickle bar, a side delivery rake, and a NH 67 baler. My tractor is only 25 HP but actually does pretty good with this equipment. Lately my sickle bar has been more and more unreliable and has broken down on me the last two cuttings. I got tired of it and found a 2020 model Ibex TS51C drum more for a good deal on FB marketplace.

This mower is rated as needing 20 PTO HP, and is marketed specifically for smaller tractors like mine. I can run it okay but I found it takes quite a bit to get it started. I have to quickly engage and disegage the PTO 4-5 times with the engine at about 1300rpm to keep the engine from stalling while the mower gets up to speed. This is the method recommended by the mower importer that sells them in the US.

Is it hard on my tractor to start the mower this way? I have a foot clutch for the PTO so another option would be to slowly release the clutch, but I'm concerned that could wear the clutch out. I also have the ability to add an extra 10 HP by turning out my fuel screw and removing one shim from my injection pump (IDI engine), but I was trying to wait until my warranty is up in a couple years to do that. Even then I don't think it would have quite enough torque to start this mower at low speed.

 

[jeepcoma]

On smaller two-wheeled tractors the procedure you're describing is called "bump starting". These smaller engines don't have a ton of torque or rotational mass to be able to dump the PTO clutch in one go without stalling when engaging some of the heavier rotational implements like stump grinders and flail mowers. This requires "bumping" the PTO clutch a bit at a time to get the implement up to speed before fully engaging the clutch and locking the implement speed to the PTO speed with full engagement. This sounds like what you are describing.

I've been doing that for years on my 2-wheel Grillo 110D to spin up big flail mowers, brush hogs, stump grinders... anything with a lot of rotating mass requires this technique. I'm sure it's more wear doing that than engaging the 72" cutter bar which has very little mass, but I don't consider it "harmful", any more so than using wheel brakes is "harmful" to the brake liners (in other words, it is, but that's what it's designed to do as a wear part). I think the main issue with these small PTO clutches is heat - there's no where for it to go. Continual slippage will burn the clutch right out for sure, but short periods are fine. Starter motors are in the same boat (nowhere for heat to go), and pretty much all of them say "crank for no more than 10-15 seconds before allowing starter to cool". I think if you ride your PTO clutch for no more than 10 seconds to get an implement up to speed, you'll be fine. A few "bumps" of the clutch to get the implement up to speed and using a wear part for its purpose is the right way to go - far better than revving the engine and dropping the clutch, dumping the load onto the crankshaft and wrist pins and all sorts of things that when they break will be far more expensive and inconvenient that replacing a clutch.

For what it's worth, I've only had to replace my clutch once. That was after loaning my tractor to someone else...

 

[SPYDERLK]

Only you can be sure of this by the indications you get. But I would favor feathering the PTO clutch starting at the 1300 RPM free speed, letting the engine lug down and the mower spin up for about a second, and then just getting off the clutch. It would probably nearly stall as the engine fully picked up the load but it would be a single relatively smooth cycle. Then dont stop the mower til youre done.