That looks like an old Rotax shifter motor, 12x series, It’s not a Max.
Not many people are familiar with those motors these days, you might have to do a little “discovery” to get it running.
As Steen pointed out, that starter is likely turning the motor the wrong direction. Those motors came with different ignition types over the years so figuring out how it should be connected could be fun.
See if you can verify it is sparking, and troubleshoot from there. Remove the plug from the head, take an old plug, open the gap to about 4mm. Turn the motor over by hand with the wheels and see if it sparks.