I didn't recognize the TS410 model, but looking it up, it is a Cut Off saw....probably based upon a Stihl chainsaw. It sounds like it is working normally....as the decompression valve makes a real difference in how hard it is to pull start one of these bigger Stihl engines. I did notice that this model is supposed to be equipped with the Stihl "Easy Start" system, which winds up a spring in the rope starter, then uses the spring to crank the engine. You might check to see that this spring mechanism is working properly.
