I have the Murray model 40504x92A and it will not start with the key. I can however start it by jumping power straight to the starter. Once it starts it runs fine until I start to release the clutch. It will start to die but if it is depressed again it keeps running, however if you try to engage the blade it instantly dies. I have replaced all three safety switches with brand new ones. Any ideas on where to look or what to do to fix this issue?

Thanks in advance
Tim