So Link tech got back to me and said there was noise on the trigger causing the fuel pump to prime and asked to check again with the CAS disconnected . So i did. It worked. Pump now primes once and not again and again. I also have an old CAS lying around so plugged that one in to see. Again perfect. It seems the CAS is faulty. The thing is i bought a new electronic bit that fits inside the casing from a aussie company. Seems its Faulty. Have to get on to them about it Thank you Dan