I have replaced the slave solenoid on an older 4.3L three times in last year. The last one was an original Mercury part that only lasted about 6 months. Each time after replacing the boat starts fine from the ignition switch multiple times for maybe the next month or so and then stops. Only way to start is to jump the slave solenoid and boat fires right up. I tested the ground at the solenoid and it is good. Also checked the yellow/red and test light shows voltage as well. What could cause the solenoids to fail so often. As soon as I install a new slave solenoid the boat fires right up using the key. Using the troubleshooting guide from Don S. on starting issues I always end up with a bad solenoid. Anyone ever have a similar issue? Thanks.