Engine Misfire: Too Much Fuel Injection?

Hello,
I have a small two-cylinder engine here with two inline injection pumps. The injection pumps were seized because the engine had been sitting for a long time. I disassembled them, and the fuel delivery volume is the same, but I can't test them any further. The injection timing also seems to be correct.
The engine is now "knocking," similar to a misfire, but it's a diesel engine. There's unburned diesel fuel in the combustion chamber, meaning the injection amount is too high, or what else could be causing this?
Wenn der Einspritzdruck zu niedrig wäre, die Injektoren etwas hätten würde er wohl gar nicht starten ? Stbut it quickly deteriorates.
Before I send the adjustment pumps in, I'd like to get a preliminary estimate.
Thank you!, Peter.

Hello,

Most likely, regular diesel fuel from a gas station was used, which, due to the biodiesel content, hardened over the years. This then "glued" the injection system.

So, make sure to rinse everything thoroughly. It's also possible that the injector nozzle is clogged.

"Knallen" as a sound can occur, for example, when...
- Head gasket leak or valve leak.
- Fuel injector is leaking/dripping.
- premature injection start (are the gears/belt twisted?)

For diesel vehicles that are stored for extended periods, I recommend using the premium diesel fuels offered by these suppliers that do not contain biodiesel.

Best regards, Rainer.

PS: https://www.buymeacoffee.com/Dieselschrauber will not be rejected

Or, if it's a stationary engine used for heating purposes, it would likely run on ordinary heating oil.

Oh, could it be related to the ZKD (cylinder head gasket)? Yes, I thought it might have been leaking there, but I assumed it was due to the pressure surge caused by the knocking or from the exhaust manifold.
"I took the opportunity to lap the valves. The compression feels good, but I'll measure it more precisely. This probably explains why there was unburned diesel in the combustion chamber; if the compression is insufficient, not everything burns?"
The piston protrusion may be slightly too small; it should ideally be around 0.1-0.2 mm, but it's currently flush.

By the way, I think there's biodiesel in regular diesel, but is there any biodiesel in this "Excellium" fuel?