I'm having some problems with the starter on my Merc 115. The starter will randomly not engage into the flywheel. Always seems to happen towards the end of the day of boating. Sometimes when I try to start the motor the starter will just spin at high speed without moving up into the flywheel teeth. I will pry it up to the teeth and hit the key, starting the boat. I have lubed the shaft with white litium grease and still have the problem. The battery is brand new and had it load tested, good. Thought maybe wasn't charging the battery so had it tested and replaced the regulator. Seems when I put the charger on the battery that it is low on charge. I should go through and check and brush all connections. Any other ideas on what could be going on. Dealership tells me to replace the starter for $$$$ Thanks for the help