Yamaha HPDI Idle Problem

[Whos your Daddy]

I recently replaced the powerhead on my Yamaha 200 HPDI. When I picked it up from the dealer and went to break the powerhead in it would not idle. It idles for a while then slowly starts to die and then dies. If you give it some gas , it runs OK , but as soon as you put it in neutral , it dies. It runs fine when it is on the muffs and idles fine , but when it is in the water , it does not idle. It is back at the dealer and they are searching but have not been able to find anything wrong yet. Any suggestions ?

[boats.net]

It would hard to say without looking at it, It could be as simple as an ruptured fuel pump diaphram and running too rich on fuel.