[Hobgoblin]

Ozsail,

I had a similar problem when storing last winter.It seemed the system was clogged by freshwater clam''s,due to docking inland and lying un-used for a month end of september.
I was told the engine sucks up "baby-clams" and they grow quickly the first few weeks,clogging the system.As it seems the alu-alloy is a good foothold for both clams and dirt/salt.
Good luck,

Hobgoblin