Yanmar RS-240 through RS-330 implements: what can you do with 24 to 33 hp?
What implements can you realistically hang behind a Yanmar RS-240, RS-270, RS-300 or RS-330? In this article we cover the three-point lift, the PTO, the electrically operated hydraulics and the automatic depth and levelling control (UFO), and translate the horsepower and measured lift and pull force into concrete implement choices.
Suitable for the entire series: Yanmar Forte Rice Special RS-240, RS-270, RS-300 and RS-330 (also known as RS24, RS27, RS30 and RS33), including the R, S, J, U, V and Q versions.
Yanmar RS series three-point lift and hydraulics
The lift is a category JIS I three-point hitch with position control: the position of the lever determines the height of the implement, and that position is held. What's special about the RS series is the electrically controlled quick lift: next to the lever there's a toggle switch that lets you raise the implement to the set height and lower it again in one motion at the headland. The hydraulic pump delivers 21 to 24 l/min at around 15.3 MPa; the measured lift capacity at the ball ends is approximately 1235–1245 kgf. A lowering speed valve (油圧ストップ/slow return) under the seat controls how fast the implement lowers — turned all the way in, it locks the implement in position, handy during transport. Check chains limit the sideways play of the lower links.
Yanmar RS series PTO: three speeds plus reverse
The PTO shaft (35 mm, JIS) has three forward speeds and one reverse — on the RS-240/270 these are 550, 796 and 1270 rpm (reverse 665), on the RS-300/330 592, 857 and 1367 rpm (reverse 716). The lowest setting corresponds to the standard "540" setting for implements: use this for rotary tillers, flail mowers and other standard implements, and always follow the speed prescribed by the implement manufacturer. The PTO reverse setting is intended for special applications (for example clearing a jammed rotary tiller) — use it with caution, incorrect use can damage the implement. Put the cover on the shaft when not in use and grease the splines.
UFO: automatic depth and levelling control
The U version has Yanmar's UFO system: sensors on the rotor cover continuously measure the working depth, and an actuator motor automatically keeps the rotary tiller at the set depth and level, even on uneven ground. This gives a tight, even tilling pattern without you having to make adjustments yourself. As an owner, keep in mind that this system depends on a smoothly running sensor cable and a properly functioning actuator motor; a stiffened cable is a known wear point (see the troubleshooting blog). The S version lacks the electric implement switch and the associated automation — deliberately kept simple.
What can you realistically do with 24 to 33 hp?
Important to understand: the number on the engine cover is the engine power, but at the PTO shaft you retain about 90 percent of that (measured: 18.3 to 22.3 kW), and the pull force at the drawbar is a whole other matter — that's determined mainly by weight and grip. Rules of thumb per implement:
| Implement | RS-240 / RS-270 | RS-300 / RS-330 |
|---|---|---|
| Rotary tiller | 150 – 170 cm | 170 – 180 cm |
| Flail mower | 135 – 150 cm | 150 – 160 cm |
| Plough | 1-furrow, light 2-furrow | 2-furrow (share ± 25 cm) |
| Cultivator/combinator | 140 – 160 cm | 160 – 180 cm |
| Tipping trailer (with overrun brake) | 1.5 tonnes | 1.5 – 2 tonnes |
| Snow plough / sweeper | 140 – 150 cm | 150 – 160 cm |
As a reference: Yanmar supplied the series from the factory with its own rotor of 160 cm (RS-240), 170 cm (RS-270/300) or 180 cm (RS-330) — so that's the tiller size the manufacturer designed the machine for itself. For PTO implements that demand a lot of power (flail mowing in heavy grass, deep tillage) you'll clearly notice the difference between 24 and 33 hp; for towing, weight matters most, and there's less difference between the 1140 kg of the RS-240 and the 1250 kg of the RS-330 than the model numbers might suggest. Use front weights with heavy towed implements — the manual also prescribes these to keep the front wheels on the ground.
Connecting and disconnecting implements: working safely
Connect on flat, hard ground: lower links onto the implement, insert the locking pins, then the top link and finally the PTO shaft (engine off!). After connecting, check that the check chains limit the sideways play and that the PTO shaft doesn't contact anything when lifting. And the most important rule from the manual: never start the engine while the "implement raised" light is on — the lift could shoot up unexpectedly.
