An engine that runs fine at start-up and with a no-load idle .... and
then stalls when load (putting it in gear) is applied is a classic
symptom of a blown head gasket. When was the last time your torqued
down the cylinder head?

Rob wrote:
Help my Bukh engine stalls when manoeuvring.
My 20 hp Bukh runs like a sewing machine until it is warm and I put
the throttle in neutral. It simply stops most of the time.
I have installed an electric pump near the tank so the system is
permanently filled with diesel.
I have checked the valve clearance, I have renewed the atomisers,
I have checked the filters for dirt or water.
After the engine stops it will start again quite easily.
I have checked the stopvalve.
Who knows the reason?