How can I fix my HC-1000 hedge trimmer?

Dear Sir / Madam,
I have a problem with my Echo HC-1000 hedge trimmer. It starts very easily, then, after it has reached working temperature, it stops. I have to allow it to cool down before it can be re-started, but then, after a few minutes, it stops again. I have to allow it to cool down again before re-starting, etc, etc,

I have checked the unit and found that, when it has stopped, there is no spark (no high tension voltage) at the plug then, after it has cooled down, I get a spark. I put the plug back in and it starts easily.

Is the problem with the ignition module?

regards,
Javaid,