VE...F - uncontrolled overspeeding

Hi,

I have a 1.6L swirl chamber engine on a harvesting machine.
It features a Bosch axial piston distributor pump with centrifugal force control.
Without residue, without LDA.

The problem is that the engine gets stuck at a high RPM, or, above a certain RPM, it starts to rev uncontrollably, likely to the point of destruction if I don't shut it off beforehand.
The pump appears to be in good condition; I took it out and completely disassembled it, and I didn't find anything unusual.
I can adjust the air screw until the engine idles at its maximum speed. Then, I turn it back in until the engine responds to throttle input, and the problem with the over-revving reappears. The warmer the engine gets, the more problematic it becomes.

If the voltage is briefly interrupted to the ELAB (Electronic Load Adapter) during high-speed operation, the situation normalizes, and the speed returns to the low-level (LL) setting.


I've tried just about everything, but I've never seen such behavior in a distributor pump .

Does anyone have any ideas?


Greetings.
John.

Perhaps it's already running with engine oil, and the crankcase ventilation is working correctly? Where is she going?

Best regards, Rainer.

That was my thought too - that's why it's disconnected/switched off.

I took it apart again, disassembled it into all its individual components, and reassembled it - nothing out of the ordinary.

Tomorrow, she will be put to the test...let's see .

Now she's being put to the test, and she's definitely not backing down.
It appears the issue lies with the shaft of the adjustment mechanism, which will now be replaced with a spring (like in the older system).

It's working again as it should .