hi mitch
i know the problems of these engines
they are a pain in the ass because they are wrong build
it only needs a different diffusor
a radial one
its very simple , the engine needs air , but dont get it because of the wrong diffusor build
but i am sorry to say , i cant help you at the moment because i am very bussy , and i dont have the machines anymore to make them

but then you know what is the problem
regards
Martin.