Kubota 05 Series Fuel, Injection and Starting

Want to understand how the Kubota 05 series fuel system and starting works exactly? In this guide, we'll walk through the entire fuel system, from the feed pump to the injector, with the correct injection pressure and timing. Then you'll read step by step how to bleed the system and how to properly preheat and cold start it. Exactly the knowledge you need when the engine is reluctant to start.

Suitable for the entire series: D905, D1005, D1105, D1305, V1205, V1305 and V1505 (incl. turbo -T/-TE and versions -E/-E2B/-E3B/-E4B).

Kubota 05 series fuel system: from tank to injector

The fuel system is clearly structured. The diesel goes from the tank through the fuel filter to the injection pump, which sends the fuel under high pressure in the correct order to the injectors. A feed pump (mechanical or electric, depending on the version) helps supply the fuel.

The injectors are prone to wear: after standing idle for a long time, the needles can seize up or start leaking, leading to hard starting, smoke, and rough running. If in doubt, have them tested for spray pressure and spray pattern. Important tightening torques in this system:

Bleeding the Kubota 05 series fuel system

If the engine has run dry, or if you've had the filter or lines off, you need to bleed the system. Air in the system is one of the most common reasons why a healthy engine won't start. The procedure:

• Fill the tank and open the fuel tap.
• Loosen the bleed screw on the fuel filter.
• Open the bleed valve on the injection pump.
• Do you have an electric feed pump? Turn the key to the AC position for about 10–15 seconds to supply fuel.
• Then loosen the injector lines and crank briefly until air-free diesel comes out.
• Tighten everything back up neatly and start the engine.

If the engine keeps drawing in air despite bleeding, there's a leak on the suction side: a porous fuel hose, a loose clamp, a leaking O-ring or drain tap, or a clogged tank strainer. Check the suction side systematically. For this reason, also replace the fuel hose and clamps every 2 years.

Kubota 05 series preheating and cold starting

The 05 series uses glow plugs in the precombustion chambers to make cold starting easier. The correct starting procedure:

• Turn the ignition key to the preheat/glow position.
• Wait until the glow lamp goes out, then start.
• For a cold start, preheat for longer.
• In cold weather, it's advisable to crank briefly for about 10 seconds in the stop position first, so the oil gets pumped around, before actually starting.

The exact preheat time per outside temperature depends on the version; go by the principle of "wait until the glow lamp goes out" and preheat a bit longer in severe cold. If the engine is hard to start cold, burned-out glow plugs or too low voltage to the plugs (poor battery, ground, or wiring) are the most common causes. Then measure the glow plugs' resistance and check the voltage and ground.