Ignition causes buzz instead of start

[baksmällan]

My Yamaha 60HP Autolube usually runs nicely, but sometimes it refuses to start. When I turn the ignition I only hear a weak buzz. Other times it starts without any issues

A quick touch with a separate cable directly from the battery + to the starter motor + solves the problem :-).

Do I need a new starter relay or what could be the issue? Would that be a "type 2" relay?

Serialnumber in attached photo