Starting & operating the Kubota GL21
Suitable for the entire Kubota GL series (Grandel): GL19, GL21, GL23, GL25, GL25K, GL26, GL27, GL29, GL32 and GL33 (also GL23DJ and GL27DJ, and the Hinomoto NX series). The procedure comes from the original Kubota manual.
A Kubota GL21 start goes almost always without a hitch – as long as you follow the correct sequence. These Japanese import tractors have a few quirks, such as the safety switch under the clutch pedal and the separate stop button. Below is the complete start and stop procedure, plus an explanation of the controls and the dashboard.
Starting the Kubota GL21: step by step
This is how you start the engine according to the manual:
| Step | Action |
|---|---|
| 1 | Set the fuel valve (under the tank) to ON. |
| 2 | Put the main gear lever, shuttle lever and PTO lever in neutral. |
| 3 | Push the position lever forward so the implement lowers. |
| 4 | Pull the throttle lever to about halfway. |
| 5 | Turn the ignition key to ON: the engine will preheat. Wait until the glow plug light goes out – then preheating is complete. |
| 6 | Press the clutch pedal all the way down. Without the clutch pressed in, the safety switch blocks the starter motor. |
| 7 | Turn the key to START and release it as soon as the engine runs. |
| 8 | Let the clutch engage smoothly and let the engine warm up for about 5 minutes. |
Important: never run the starter motor for more than 10 seconds at a time. If the engine doesn't start within that time, wait at least 30 seconds before trying again – this saves the starter motor and battery. Never turn the key to START while the engine is already running.
Stopping the Kubota GL21
Move the throttle lever all the way forward (idle), turn the key to OFF and the engine will stop. If it doesn't stop – which can happen with this generation – pull the separate engine stop button all the way out. Then push that button back in, otherwise the engine won't start next time. If you hear a click 4 to 8 seconds after shutting down, that's normal – it's the stop mechanism resetting. Always remove the key.
Dashboard and Easy Checker
In addition to the hour meter/tachometer and temperature gauge, the dashboard has a row of warning lights that Kubota calls the "Easy Checker": preheating, battery charge, oil pressure, radiator/coolant and self-diagnosis. If the oil pressure or charge light comes on while working, stop immediately and find the cause – continuing to drive with the oil pressure light on will destroy the engine. If the temperature gauge enters the red zone (around 125°C), don't switch off the engine right away but let it cool down at idle, then check the coolant, V-belt and the radiator screen.
Driving with the 16/16 shuttle transmission
Use the range lever to select the range (creep, low or high), shift gears with the main lever and set the direction of travel with the shuttle lever. This gives you 16 forward and 16 reverse gears. Always operate the shuttle with the clutch pressed in and the tractor stationary. For work with the rotary tiller, use the creep gears (below 0.5 km/h); for transport, use the high range – the GL21 then reaches 14.8 km/h. Lock the pedal clutch between both brake pedals when driving on the road, and only use the steering brakes in the field. Only engage the differential lock with the heel pedal when driving straight ahead on smooth or loose ground.
Front loader or weight on the lift?
For heavy work, keep the tire pressure in mind (front 1.6 kgf/cm², 2.0 with a front loader) and hang sufficient front weight on the nose when using heavy lift implements: the manual warns that otherwise the front becomes light and the steering loses its grip.
