I have a yamaha OX66 200hp two stroke. I have just rewired the boat. I upgraded all of the wiring. I have two batteries both batteries have a 4 gauge leads to the battery switch and 4 gauge wire from the switch to the outboard. The marine shop suggested I add a fuse at each battery. I added a 40amp fuse at each battery (never had this before) while the battery switch was on, the 40 amp fuse at each battery blew when the outboard starter motor was cranking. (when bypassed the blown fuse motor flashed up and no further issues. ) I assumed a wiring error during reno, however after checking all the wire runs, my new theory is that I should not fuse the short run to the battery switch and put the 40 amp fuse between the output on the battery switch and the 4 gauge wire running to my fuse sub panel up front and not fuse the outboard leads as they are fused at the motor. I suspect the starter motor while cranking draws more than 40 amps thus the cooked fuses. Can anyone confirm the amperage draw by a starter on a 200hp and that moving the fuse is a good course of action. Or should I just put a bigger fuse at the battery or am I going down the wrong road?
Thanks
Thanks