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Browse aftermarket replacement parts for the Kubota D1803 industrial engine. Kubota 03 Series 3-cylinder industrial diesel engine.
Use filters or search by OEM part number to find the right part. Compatibility details are listed on each product page.
The D1803 is the largest 3 cylinder engine in Kubota's 03 Series and the bridge between the smaller 3 cylinder D1703 and the 4 cylinder V2403 / V2203 / V2003. The D1803 specifically uses the same bore and stroke (87 by 102.4 mm) as the V2403 4 cylinder, which means the engine internals (pistons, rings, valvetrain hardware, cylinder head) cross between the D1803 3 cylinder and the V2403 4 cylinder despite the different cylinder counts. The D1803 is the only Kubota 3 cylinder engine offered with both turbocharged (T) and turbocharged plus intercooled (TI) common rail (CR) variants, which delivers diesel power density approaching 4 cylinder output from a more compact 3 cylinder package. The D1803 P1 Hybrid variant pairs the engine with a parallel hybrid electric system for emerging zero emission worksite applications.
In the Kubota equipment lineup the D1803 sees use in larger M Series tractors, larger MX Series compact tractors, select KX 4 Series mini excavators, and a number of OEM industrial applications where the 50 horsepower band is the design target. Outside Kubota, the D1803-CR-TI-E4-BG generator package variant is widely used in standby and prime power generators where the constant load operation matches the engine's torque characteristics.
Cooling and electrical service is the leading category for the D1803 because the higher power density of the turbocharged variants puts more thermal and electrical load through the support systems than the naturally aspirated D1703 sibling. Cooling Fan 16665-74110 covers the engine cooling fan service. Alternator 16404-64012 covers the electrical generation service (shared with the D1703 because both engines use the same alternator bracket and pulley). Thermostat Assembly 1A021-73012 covers the cooling thermostat housing on the D1803 (the same assembly is shared across the D1703 sibling and several KX excavator chassis). Oil Pressure Switch 15841-39010 covers the lubrication pressure circuit.
Starter motor 17123-63016 is the V2203 family starter that is also used on the D1803 because the bell housing pattern is shared across the 03 Series. Fuel system service uses Fuel Filter 1E786-43060 (specifically tied to the D1803 common rail Tier 4 final fuel system, distinct from the older mechanical injection D1803-M-DI primary filter). The CR-TI-E4 / CR-T-E5 common rail variants use a different fuel injection pump and aftertreatment than the older mechanical injection D1803-M-DI-E2B / E3B variants, so verify your engine model designation against the part listing before ordering high pressure fuel system parts. Smaller assembly hardware (Oil Gauge Plug 1G513-36550, Guide Oil Gauge 17456-36420) is typically ordered alongside larger service items.
Kubota D1703
Kubota V2403
Kubota V2203
Kubota V2003
Kubota Air Filters
Kubota Engine Oil Filters
Kubota Compact Tractor Parts
Kubota Utility Tractor Parts
Kubota Excavator Parts
Kubota Engine Parts
Kubota Parts
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