Pressure washer will not start after replacing carburetor and cylinder head
Since this is a pressure washer and no one has mentioned it - when I have a hard time starting one, I will hold the trigger of the spray wand while starting so the pump can't build any pressure. Unless the engine is in perfect "start on the first pull" condition, this is a requirement because the pump will build pressure and make it harder for the engine to turn.

You used to be a mechanic, so I'm not going to talk about checking for fuel, spark and air - I assume you've done all that, so we are left with why the engine is hard to pull start and for me, its normally the compressor.