Engine loses revs then increases, 1961 Normag Dies

The Normag engine I have will not run properly. When started and given full throttle it revs up allright but then loses power, almost dies and then revs up again. This cycle continues even if the throttle is kept at maximum. During this it smokes a LOT from the exhaust, mostly (95%) white smoke tinged with black.

The engine is a 1-cylinder Normag Zorge 2-stroke diesel (it has an extra piston for pressurizing air for purging). It is 18 Horsepower by design but now has almost no usable power.

It starts allright but idles very badly and is giving worrying klonking noises when idling.

What to do? I hope someone can help me locating the problem. Thanks in advance.

Best regards
Jeppe L.

• Link to zip-file with a pdf cutout diagram of the engine.

Well I should have mentioned that it smokes a LOT! So I think there is fuel but maybe too much or at the wrong time.

It is probably the injector, that is my best bet right now. I have professionals working on the injector but they cannot find the make of it. There is only a logo on it, no name.

The logo is inside a triagle and consists of a square seperated into two halves by a line and with a small line on each side of the bottom half and three small lines on the top of the other half. (not easy to visualize, I know).

Thanks for your input.

best regards
Jeppe L.