so, what does that rack damper bolt (617) actually do?
 

does it do more than simply adjust idle? what 'rack' does it adjust? how to make a 617 not shake at idle? is it possible??

It dampens the rack. ;)

My best guess is that the rack is something inside the injection pump that controls how much fuel is injected, by dampening it, it cancels out the vibration of the engine from creating a resonating injection of fuel that makes the vibration worse, someone pleasr correct me if i'm wrong...

As far as I understand that is correct.

I'm sure somebody who has commited the Bosch manual to memory will chime in soon. :D

Was ist der rack?
 

I to - as a newbie - have wondered what the rack actually is. I asked the same question a while back and never got a posting that explained what the rack in the IP does.

There are lots of postings on how to adjust it, nothing on what you are actually changing by adjusting said bolt.

My engine doesn't vibrate a lot at idle (certainly compared to the tractor :)) so I have never bothered to mess with it.

Sorry I couldn't find a photo but here goes..........o o o o o.(the o's=valves & underline=rack)............The rack is a geared shaft in the IP that turns a tapered plunger in the fuel delivery valve to control the amount of fuel delivered with each stroke. When the rack returns to idle, the dampner cushions the return for a more gradual decrease at the very end of its travel.

Yes that concept is correct and let me add on each plunger there is a groove in which allows fuel to leak out to the bleed holes to limit the pressure. The "control" rack turns the plunger so the grooves can meet up with the bleed hole.

Here is the pics that your looking for.

I have an IP completely dissasembled and that rack itself is pretty cool

truly great information there. so when I adjust the rack damper I'm not adjusting idle speed, just idle shakyness? what adjusts idle speed then?

There's an idle adjusting screw on the IP on the block side. It has a slotted head and a lock nut.

why would we want to "dampen" any "rack"? lol lol

Here is a picture of the old silver damper and the new gold damper. (The blue lines in the picture are camera artifacts).

I do not know exactly what the rack dampner does...
but I know the MB engineers designed it so that future wear ( excess play ) could be ' taken out' by adjusting it..

Recycled
 

For new members.
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