I`m not a boat mechanic but have a lot of vehicle repairs experience. I am helping a guy with a starter concern. Starter was not working. We installed a new starter, yes wired it correctly, try to start it an nothing. checked the starter and the new 100 amp fuse was blown, also solenoid was burned. thing just a bad starter. installed a new one, tried to start but burned up again. install number 3 starter. cranked three times and ran engine maybe 10 secound each time out of water. put in water to take it out for a spin, no start. back out of water and check starter burned up. the whole time we made sure batterys were up on charge. number 4 starter did not install a fuse, fried starter first crank did not even make a sound, just burned up another starter. all wires have been checked for correctness and for bad connections, all good. HELP AND THANK YOU. ps this is a 2015 mercury curiser 5.0 GM PORT FUEL inboard engine.