Fuel Injector for Doosan D34 & Bobcat Skid Steer Loaders
The 7261663 fuel injector is a direct-replacement diesel injector built for Doosan D-series engines and Bobcat compact equipment. It atomizes pressurized diesel into a fine mist for efficient combustion in engines like the D34, D34T, D35S, D40S, D50S, D60S, D60T, D74, D74T, and D90S. If your Bobcat loader is blowing black smoke, knocking under load, or idling rough, a failing injector is often the culprit.
Compatibility — Doosan Engines
| Engine Model | Fuel Type | Application |
|---|---|---|
| D34 / D34T | Diesel | Skid Steer, Compact Track Loader |
| D35S | Diesel | Wheel Loader |
| D40S | Diesel | Excavator, Mini Excavator |
| D50S | Diesel | Compact Excavator |
| D60S / D60T | Diesel | Skid Steer, Tracked Loader |
| D74 / D74T | Diesel | Backhoe, Tool Carrier |
| D90S | Diesel | Telehandler, Large Frame Loader |
Compatibility — Bobcat Equipment
| Bobcat Model | Type |
|---|---|
| A770 | All-Wheel Steer Loader |
| S630, S650, S750, S770, S850 | Skid Steer Loader |
| T630, T650, T750, T770, T870 | Compact Track Loader |
| V519, V723 | VersaHandler |
| V923 | VersaHandler |
Replaces OEM Part Numbers
Direct cross-reference for the following part numbers:
• 400903-0043E • 28347042 • 7261663 • 65.08171-7245 • 65.07674-7223 • 65.07674-7247 • 65.07674-7263 • 65.07674-7265 • 65.07674-7266 • 65.08171-7211 • 65.08171-7229 • 65.08171-7231
Signs You Need a New Injector
On a Doosan D34 in a Bobcat S750, a single failing injector can drop output by roughly 25%. Watch for these symptoms:
- Black or gray exhaust smoke — especially under load when pushing dirt or lifting a full bucket
- Metallic knocking or nailing sound — from the engine block, more noticeable at higher RPM
- Rough or uneven idle — the whole machine shakes at low throttle
- Poor throttle response — hesitation when you push the joystick forward
- Higher fuel consumption — you’re filling up more often for the same work
- Diesel smell in the oil — indicates fuel is leaking past the injector seat into the crankcase
Replace as a Set
It’s common practice in the field to change all injectors at once rather than one at a time. Mixing old and new injectors means uneven spray patterns — the new one works harder and burns out faster. If your machine has been running with a bad injector for a while, the uneven combustion also clogs the DPF faster and puts more stress on the turbocharger.
Frequently Asked Questions
Will this injector fit my Bobcat S750?
Yes. The 7261663 injector fits all Bobcat S750 models equipped with the Doosan D34 or D34T engine. Verify your engine code on the data plate near the engine block before ordering.
Do I need to program or calibrate the injector after installation?
On most Doosan D-series engines this is a mechanical injector — no electronic programming needed. However, some newer D34T models with electronic control may require dealer-level calibration. Check your service manual.
How many injectors does the Doosan D34 have?
The D34 is a 4-cylinder engine with 4 injectors total. We recommend replacing all four at once for even fuel delivery and longer service life.
What’s the typical labor time for replacement?
On a Bobcat S750 or T750, expect 2 to 3 hours of shop time. The injector is accessible after removing the valve cover and fuel return lines. No cab removal needed on most models.






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