I have an 82 gallon plastic fuel tank in my boat. I think that the threads to the fittings have been damaged due to an over-aggressive and mis- aligned turn of the wrench. The fix was done on open water with high seas...it was a quick fix that got us home. Problem is I can not get the fittings off. It feels stripped and the innermost fitting which I think is called the molded insert, needs replaced. Any suggestions? I'm waiting on an email from Moeller Marine.