The Mercathode should have been hooked directly to the battery, not the starter. That way if you have a battery switch and shut it off, it doesn't stop the Mercathode from working.
thank you Don. i will run it to my blue sea ST Blade Fuse Block in the back of the boat tomorrow and hook it to a 20 amp blade fuse. i suppose i need to look for the black wire as well and hook it up to the battery neg.