This is my first post so bare with me. I have a 2003 Tracker Pro 175 with a 2003 Tracker 50HP outboard. Went fishing yesterday & boat was preforming great. I was back in a cove when I hit mud. No hard hit, just stirred up a lot of mud. After getting back into deeper water, the boat would not go forward. When I shifted into forward the boat went backward. Shift into reverse & the boat went backward. It took for ever to go 2 miles in reverse back to the launch ramp. Got the boat on the trailer & inspected for damage to prop & lower unit. No damage detected……...Where should I begin troubleshooting. What should I look for?