Haskel Mini Sport Partial Boost

[barbarossa]

I have a Haskel Mini Sport that has been working well for a couple year and has recently started to only boost about 600 PSI over the input. I took it apart and gave it a lube job, but it still doesn't seem to boost well. Adjustments to the exhaust manifold doesn't help.

 

[tbone1004]

It's probably a check valve issue. They are notoriously finicky. Take check valves apart and clean, reassemble. Should help. If not, will either require rebuilding them, or what many do, replacing with Swagelok/Parker check valves.