If your Komatsu FG25SHT-16 forklift starts and runs for about 10 minutes before shutting down due to fuel starvation, there could be a few potential causes for this issue. Here are some thoughts and troubleshooting steps you can consider:

Fuel supply issues: Although you mentioned that there is plenty of fuel from the converter to the injector, it's worth double-checking the entire fuel system for any blockages, restrictions, or leaks. Inspect the fuel lines, filters, and connections to ensure proper fuel flow.

Fuel pump malfunction: The fuel pump is responsible for delivering fuel from the tank to the engine. If it's failing intermittently or not providing sufficient fuel pressure, it could lead to fuel starvation after some runtime. Have the fuel pump checked for proper operation and pressure output.

Clogged fuel injectors: Over time, fuel injectors can become clogged or restricted, leading to insufficient fuel delivery. This can result in the engine running for a short period before shutting down. Consider having the fuel injectors cleaned or, if necessary, replaced.

Ignition system issues: While fuel-related problems are the primary suspects, it's also worth checking the ignition system components. Faulty ignition coils, spark plugs, or the ignition control module can cause intermittent engine shutdowns. Ensure that the spark plugs are clean, properly gapped, and in good condition.

Engine overheating: If the forklift's engine is overheating, it can trigger a shutdown as a safety measure. Check the cooling system components, such as the radiator, coolant levels, water pump, and thermostat, to ensure proper cooling. Inspect for any leaks or blockages that may be causing overheating.

Electrical issues: Faulty electrical connections, wiring problems, or a failing electrical component can also cause intermittent shutdowns. Inspect the wiring harness, connectors, and battery connections for any signs of damage or loose connections.

Considering the complexity of forklift machinery, it may be beneficial to consult with a qualified technician or Komatsu service center to diagnose and resolve the issue effectively. They will have access to specific technical information and diagnostic tools to identify the underlying cause of the problem.