Did you know the starter motor brushes arrived not made by yanmar. They are Hitachi. The starter is used on a number of vehicles. One is a Nissan Tilda.
It’s simple to replace the brushes.
They are really inexpensive and a very valuable spare part.
That said, sometimes if the brushes get worn out, but still half work, they can ark and damage the copper contacts. Then it is a new starter motor.
In the photo below, it’s easy to see the difference in the length of the old brushes compared to the new brushes.
