I have copied the images from the workshop manual of my LD28. Should SEM448 not be the "Correct" one and SEM449 the "Wrong" one. My logic tells me that if the engine rotates in a clock wise position with the sprocket on the crank being the "driver" and the cam sprocket the "slave" or "follower" in the case where the chain is stretched with Mark B on the sprocket and Mark A is on the static back plate, the "follower" will pass the static mark later.
Reason for this long explanation: my LD28 is not running 100% and my sprocket markings are as per SEM448. How important is the correct position of the marks and does it have a considerable effect on the running of the engine?