Pump lever tampered with

[alb_qwerti]

Dear members,

It's my first post but this forum was really helpful for me in the last weeks.
I tuned my '64 230 SL as per linkage tour and now she run much much better.
Ignition and compression were already fine.

There is still a progression hesitation (lean out) even if run little rich at idle and perfect at full throttle.
If I enrich the overall mixture the hesitation disappear but become too rich at idle and normal running.

I suspect that the pump lever was misadjusted, rotated in the pump control shaft.
Is there a way to know the original position of the lever in relation with the control shaft?

Unfortunately I don't have any service manual of the car or the pump.
Maybe this information is available there.

Many thanks and compliments for the greatly detailed site and discussion forum.

Alberto

[stickandrudderman]

Setting the pump lever angle is not possible without specialist knowledge and equipment. However, with the use of a wide band AFR meter you can adjust the partial and full load screws in the pump. Search the tech manual for how to do it.

[ctaylor738]

If you haven't already done this, I suggest you slowly open the throttle with the shaft across the engine.  While you do this, carefully observe the the pump lever and the lever on the throttle plate to be sure that they both move at the exact same time.  You may have worn balls and sockets that can cause a delay in opening at either end.  That could contribute to the hesitation.

Good luck,

CT

[alb_qwerti]

Many thanks for your answers
I saw in the tech manual the black and white screws you are talking about but to have access to them you must remove the pump or at least the back cover.
I think more likely that an old school carburettors mechanic had messed up the stop screw on the lever to correct some idle related problems.

All that I need should be the distance between the rack and its bottom stop when the lever is on its closed stop with hot engine (WRD lever pushed all the way in).

If anybody have an R11 pump on hand... this could be the solution. 

For CT:
The levers travels both from idle stop to full throttle stop and start from the idle stop simultaneously.
I had a worn ball socket at the throttle lever that I changed yesterday.

Thanks,
Alberto

[ja17]

Hello Alberto,

That is the one adjustment which should never be tampered with. It moves the critical compound cam inside the pump. It I the base from which all other pump adjustments and devices are set. Get familiar with the split linkage test so you can understand what the mixture is first of all.

Also welcome to the group. My father's name was Alberto also, his family was from Alvito (in the hills south of Rome).