IP Full Load Adjustment Procedure for the MW and M pumps

OM616

10mm MW

572

06-10-2012, 11:57 AM #194

(06-09-2012, 10:34 AM)tee51397 MW Pump / RW governor
'83 240D

I'm hoping you experts can help me understand a few things and answer a question.

If one wanted to increase the strength of the idle governor / it's ability to regulate idle and not the idle speed itself would the correct adjustment be made to the bump stop spring? If so would the adjustment be made clockwise?

Second with minimum idle set shouldn't the only way it would dip below the set point be with an external force pulling the rack to the cut-off point? I guess what i'm really getting at is with the vertical stop and all external linkages and springs removed so that the throttle lever is totally free why would the governor not maintain the idle set point instead of continuing to drop to the cut-off point? Shouldn't the force of the flyweights/springs be enough to overcome a free lever if everything was set correctly?

I've really enjoyed reading this and many other threads so thanks for all the cumulative information.

-Tristan-

The Bump Stop comes into play only when a load has been removed and the engine starts to rev up, at that point the fly weights over come the Idle Governor Spring and contacts the Bump Stop to momentarily bring the rack to or close to cut off, then when the engine speed has slowed down to the Recovery Speed, the Bump Stop pushes the Idle Governor Spring and Rack back in to Idle operation range.

If you turn in the Bump stop, it will increase the force required from the fly weights (higher speed) to compress the Bump Stop and bring the rack to the cut off point, and it will raise the Recovery Speed, this will result in a potentially uncontrollable high speed idle situation.

Here is the scenario where the Bump Stop could use an adjustment. Lets say the Idle governor Spring Tension is correct, the engine is idling with no loads. Then at the same time, the A/C is turned on, heater turned on full, head lights come on, and the trans is put into drive, the Idle governor will increase power to maintain idle with in a reasonable range, everything is good. Now just as the loads were applied, they are removed, and given the rack position required to maintain the loads will make the engine take off, the flyweight force pushes the rack and Bump Stop to the Cut Off point for a moment, but if the Bump Stop is too week, it will not be able to push the Fly Weights back when the engine reaches the Recover speed and the engine will stall.

If the Engine Idle speed is low or is week (stalls or struggles to maintain idle speed when loads are applied), that is the Idle Governor Spring Tension, If the engine only stalls or really struggles to recover when loads are removed, that is the Bump Stop that need a slight adjustment.

I get the impression that you are trying to do something with this engine than power a car correct?