If your talking about battery to motor starting circuit, there should be a Solenoid mounted on the motor case. If there is, use a standard crimped 6-8 awg (short as possible) direct from the battery to the solenoid threaded end labelled battery. Be sure to keep the cable isolated from sharp engine components (stationary and/or throttle cables or levers. But it is not fused. The solenoid has two or three other leads; one will go directly to the starter (another 6-8 awg lead. The other one 24 awg is to the ignition switch and will be fused somewhere close to the ignition switch. Once the ignition switch is energized, it will connect the two large terminals on the solenoid switch (battery lead/Starter motor lead) together which will provide all the required amperage to the starter motor. Release the switch and it, in turn cuts the connection between the battery and starter motor.