setting the fine-adjustment on pump for idle

[enochbell]

Is there a way to know how the adjustment thumb-screw is oriented for the injector pump?  I thought there were 7 positions: straight up and three to either lean or rich.  But the adjuster has no stop, so mine could be anywhere, for all I can tell?  I don't have an exhaust gas analyzer, the car idles fine but it does not seem to change with different settings (yes, I am changing it with the engine stopped).  I would just like to start with the adjustment in the middle position, but I have no idea how to get there.  Can someone offer some advice?

Thanks,

Greg

'64 230sl, fully sorted out...ooops, spoke too soon

[A Dalton]

G

 The adjuster is spring loaded in the sense that it is dis-engaged from the screw that it turns when it is at it's normal/neutral state. [Out]. It has no set position until it is pushed into the pump.
  So,  in order for it to change the adjuster screw in the pump, it first has to be pushed IN  and turned slowly until you feel it slip into a screw slot. It is only then that it is engaged into the adjuster slot and only now will you be able to turn it [ you will then feel/hears the little 'clicks' as you turn it . Each click is a set amount of turn/degree increment . I like to start w/two clicks and then tweak down to one at a time for final balance.
 The reason this knob is spring loaded is b/c the adjuster slot that it engages in the pumps interior is spinning when the engine is running.  So, the spring loading keeps the knob out of the screw slot
and can only be engaged when the pump is not turning and the knob is pushed in to engage it. [ meaning , never push the knob in w/engine running].  This is the reason you do not see a set position on the knob. When it is in it normal state , it has NO position, as it is simply rotating free as you turn it  [ Neutral].  It only has a definate position when it is engaged in the screw slot when pushed IN.
 Simply put , there is just an adjuster screw in the pump that has to be adjusted and the knob is just a screwdriver that has to be pushed into the slot , but can't when the pump is running b/c the screw slot is turning.  So, just imagine the knob as a lillte spring loaded screwdriver ..where you have to feel around for it to get in the screw slot b/c you can not see the slot in the pump.
 Of utmost importance is these adjustments are only to be considered after all links are properly adjusted and ignition timing is set. The combo balance of idle air bleed /pump fuel mix/and RPM are the final tweaking that this  adjustment adresses..
There are some real good procedure on this in the archieves...

[enochbell]

Arthur, thanks, that is perfectly clear.  I appreciate it.

Greg

'64 230sl, fully sorted out...ooops, spoke too soon

[Mark in KS]

Just remember that turning the knob (when it's engaged), CW will make the idle fuel mix richer and turning it CCW, will make it leaner.  6 clicks is one revolution on the setting.

FYI

[A Dalton]

Originally posted by enochbell

Arthur, thanks, that is perfectly clear.  I appreciate it.

Greg

 Et al,
  While on the subject of the adjustment........
 Here is a picture from the JA Collection  that shows the interior adjuster/ Gov. screw arrangement.  The center one is the idle and that is the one that the knob engages when you push it in. The others are mid range and high range  adjustments . They come as a set of two b/c they are off-center, so they have to be turned the same a a set .
These require a gas Analyzer or Dino , but a good guy w/lots of experience can do them .
 If you look close at the picture , you can plainly see how the spring clip snakes it's way around ALL these screws [ pretty neat design] . Each screw has a 6 sided hex head and there is always a side/flat that is held in position by  a section of the spring clip.  So, as you turn a screw , the CLICKS are the spring locking the next hex flat of the adjuster screw ..5 screws all individually locked with one spring.
http://www.sl113.org/forums/uploaded/ja17/200461523449_governor%20adjuster%20mech.%202.JPG
I would not even attempt to discripe that without the pic...so
Tnx to JA for the aid of pic ...

[hands_aus]

A question?
When the middle screw is wound out too far to the point of not having the 'click' feel, are the other screws able to move because of the lack of tension provided by the middle screw on the springs?
What I am wondering is if the lack of tension can allow the screws to shift position and have an affect on the other speed ranges of the engine?

Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL, auto

[A Dalton]

B
 I doubt it , as the springs outside pressure on the mid/high screws is its natural state and it is those adjusters that actually contain the springs tension.. if they were not there , then it would more likely be the idle

screw that would lose the lock design of the spring.. [ notice the bottom end of the spring is open, so the outside screw heads contain it around the center screw]

[hands_aus]

quote:Originally posted by A Dalton

B
 I doubt it , as the springs outside pressure on the mid/high screws is its natural state and it is those adjusters that actually contain the springs tension.. if they were not there , then it would more likely be the idle

screw that would lose the lock design of the spring.. [ notice the bottom end of the spring is open, so the outside screw heads contain it around the center screw]

Thanks, I was speculating

Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL, auto