The mower has a Yamaha engine, the same as this one:

https://www.outdoorking-forum.com.au/forum/u...p;Words=yamaha&Search=true#Post11309


Here is some detail on a similar Yamaha, the MT110 (it may be the same engine, though the top of the cowl looks slightly different):

https://www.outdoorking-forum.com.au/forum/u...p;Words=yamaha&Search=true#Post61173