Where to get injection pump shims.. and other pump issues

[drooman]

My new to me pagoda 68 250SL ran like crap when i got it. The usual stuff...super rich, drowning in fuel, linkage all messed up, throttle stop way open, etc etc.  I've been through this before so after correcting linkage mess, ignition, vacuum leaks, injector service/ testing, valve adjustment and a change from "Gaso-oil" to just "motor oil" I went after the richness issue. First thing i do at this point is a new injection pump warm running thermostat since most are shot.  Sure enough it went from super rich to....super lean. The idle mixture knob on the pump was set to full lean, probably in a futile effort of someone trying to lean it out against the literal "tide" of fuel from the failed thermostat.  I knew I would be getting into the full range mixture as well. Then the fun started:

This particular pump has the cold start solenoid and the shut off solenoid... and a "guide tube" for adjusting the full range mixture screw. I haven't seen one these guide tubes before and it's a pain in the A**!  On every other pump i've seen, there is no guide tube and a larger hole with a brass plug in it. I find this helpful because the cold start lever is right in front of that hole and that extra space allows me to angle the small screwdriver passed the lever and into the adjustment screw. With the tube the hole is so narrow, and it's a tube, so the screwdriver is channeled straight  in, straight against the lever and pushes it straight into the adjustment screw. I really don't see how one is supposed to adjust the rack with the "guide tube" unless the lever is removed. I removed the cold start solenoid so I could see this foolishness first hand.

Next issue is that the cold start solenoid lever has, over time, bashed the rack adjustment screw enough so I may not be able to adjust it even IF i could get a screwdriver on it.

My questions:

I may have to do this adjustment with shims added to the thermostat housing... where does one get these?  Not crazy about this, I have an air fuel meter and I like to do all the adjustments with that. I'm thinking the rack clicks have more precision than the shims.

How does that damn guide tube come out of the rear pump housing? is it screwed in? its round and I'm afraid to try to unscrew it lest I break the rear housing. I can pull the rear housing off in the car if I have too...wouldn't mind avoiding that.

I see many recommend to disable the cold start solenoid, and that sometimes the levers break. My car starts and runs really well, all temperatures. (it's just too lean) If i do this i would want the lever out of there (unless I can get the guide tube out) so i can adjust the rack. I see the lever is attached to an external bolt/ pin. What's the manner of removal? looks like a lot of springs/bits attached to that pin and lever.

[mrfatboy]

Regarding the shims, I assume you are talking about the oval shims under the WRD? These only affect the mixture during warm up. Once the car is at operating temperature they have no effect.

Use your CO meter to get the correct mixture when the car is hot. It seems that the PO really made a mess of things. Hopefully they didn’t touch the white & black screws in the pump.

That leaves you with the main rack screw, idle thumb screw and BC for the relative easy adjustments. It will take some time as it’s an iterative process.

There is lots of good info in the tech manual about tuning the FIP as well as a FIP simulator to play around with the settings.

[ja17]

OK you say you are now too lean. I would definitely check the BC. I know here I am about 750' above sea level and the BC extends around 22mm past the hexnut.
If the BC and everything else is ok,  the round shims under the barometric compensator (BC) will adjust the pump at all speed ranges and temperatures. Adding a shim will richen the whole rpm range. I would start off just loosening it temporarily and count the turns or partial turn counterclockwise. It won't take much. If you find a "sweet spot" you can add the correct thickness of shims to equal the amount of turn. After making this whole rpm adjustment, you will need to go back and adjust the idle mixture and possibly the WRD. If your not real good with "split linkage testing" a CO meter is helpful.

[drooman]

Thank you guys...very helpful. I read up on the BC im going to get into that today. 

I mentioned in another post about this car that it has a 280SL engine and the pump has the later oil supply arrangement...no dipstick, no fill port.
The oil is pretty nasty in there and I'm assuming it is because the overflow port going back into the engine is at the height they want the oil level at, so with a constant supply of oil I can see how the oil in the pump may not circulate that well and collect sludge (especially with a rich running motor) i want to "change" the oil in it. what's the best way on THIS type of oil supply pump?

[Shvegel]

You could remove the firewall side cover to drain most of the oil but you risk having a leak once you put it back on. My advice is it will change itself in time.  There isn’t a huge load on anything in there (even the cam has roller followers and runs on ball bearings) so as long as it has oil I am sure it will be OK.