Here's a pic of the turbo I'm using showing the part number. I'd taken it off because the turbo / manifold gasket was blowing and needed replacing.
I put an airline to the diesel return pipe and it appears to have solved the problem.
I bought a used 185 pump and split the alloy / cast steel body, replaced the seals and it works fine.
https://www.dropbox.com/sc/f42ttqcv8...013-iaJ0UUC3La