Hydraulic engine controls

[baylabayla3288]

A friend of mine has a Ferretti 150 with MTU engines from about 1995. He has run into some issue with the hydraulic engine controls on board. They stay sluggish despite several bleeding attepts and he suspects a leak somewhere. Now unfortunately the users manual describing this system is lost and even the manufacturer is unclear. Who might have been the manufacturer that Feretti used at the time this boat was produced?

Thanks in advance for info re the manufacturer or troubleshooting hints