Re: Westerbeke - no start post inj. pump rebuild.
Cannot place what you mean by crushable heat sheat, pictures would help.
If you test all 4injectorts you can hand crank the engine and see if pump and injectors deliver.
I agree with you that the sealing of the injectors in the head is a possible problem. Better make shure that was done as per manual. Did you forget to remove the previous washers and now have two?