I found one, Ocean Options in Tiverton RI, they are the ones that service most boat yards on Cape. I was able to pull the unit and drop it off saving me a considerable amount of money.
It checked out ok, I think the new grate on the thruhull is too small causing the flow rate to slow down just enough. It is is icing up when left on automatic mode. if I keep the fan on med speed its enough to keep it from icing up. All vents are clean and the air filter is clean. I think the problem is lack of water flow. They told me if it is icing up that it has to be air flow or water flow.