Perkins no power under load

[Raymidd]

Check the hoses between turbo and manifold; a leak there will have the same effect as a blown turbo.

[Perna]

Most turbo diesels have a small pipe coming from the inlet manifold to measure the boost and allow more fueling. If this is split or leaking you don't get the extra fuel to produce the full power curve. It is basically a naturally aspirated engine. Symptoms are free reving under no load but no power to turn the propeller.

Easy to check if you can find it.