It’s been a while since we tested a sub-100hp tractor. In fact, the diminuitive 55kW/74hp Kubota M4-073 is the first model under 100hp that we’ve ever put through the Powermix test
The M4 is the smallest standard tractor in the ever growing Kubota fleet, with outputs of 66hp and 74hp. We tested the M4-073, which has the firm’s own V3307-CR-TE4, four-cylinder 3.3-litre motor under the bonnet. As an intriguing historical side note, the firm’s founder, Gonshiro Kubota, acquired the licences for engine manufacturing from Germany. So, to give a nod to Rudolf Diesel, the company has stuck with a bit of German in its engine designation: ‘E’ for one- (ein) cylinder, a ‘Z’ for the two (zwei) pot model etc, have since appeared in the motor model name. Likewise the V in this tractor’s engine represents V for vier or four. In total the Japanese giant pumps out nearly a million motors every year!
Restrained output, great characteristics
Now back to our test steed, which first had to prove itself on the dyno at the DLG test centre. Of the claimed 54.6kW/73.2hp, only 39.1kW/52.4hp reached the pto at the rather rapid rated speed of 2,400rpm. This indicates a suitably restrained engine set-up. It’s a good trait that, when the engine speed drops, the maximum power at the pto increases up to 42.8kW/57.4hp at 2,000rpm.
The Kubota engine characteristics are really convincing, with a more than 52% torque rise and no less than 139% start-off torque — these are both great stats.
And this is also noticeable when working with the little M4. Even with the 540E pto speed selected, our test candidate could start off a 10m³ tub mixer with the engine just ticking over. Not only that, but the first gear in the transport range reaches more than 10km/hr, so it can also be used to pull away under load without having to make a range change via the rather stiff gearstick.
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