Vacuum leaks?

[maddf60]

08 DF60 Just spent $1400.00 at shop going thru entire fuel system. Motor been sitting 3 years. Was fine when stored apparently not stored properly enough.
Motor idle fine but will only turn about 2800 rpm and boat won't come on plane. Usually about 4200 rpm.

When flushing motor I heard what seemed like a vacuum leak. I found a rubber hose at top of intake manifold. It's definitely a vacuum line.
Should it be connected some where? When I called the same repair shop this morning guy said he thinks it just lays there and can't tell me what it's for.

Shop lost their lead mechanic last year.

[Harper]

A picture would help. It's connected at one end?

[maddf60]

I dropped boat back off to shop so can't get a pick. But it must be connected on the one end some where because it definitely has vacuum in it.

It is along top of intake manifold goes down behind it near hi pressure fuel pump. The open end is near rear of intake back near fuel injector rail.

[2014DF25ARS]

I have a different motor - DF25A. But it DOES have a couple of open-ended hoses hanging around the intake manifold. One comes off the top of the Fuel Vapor Separator (which I've heard referred to as the VST), between the low-pressure and high-pressure fuel pumps. As I understand, that hose should just vent fuel vapors to the atmosphere. And there's another hose below the Fuel Vapor Separator which is there to drain fuel via a drain screw.