I took my boat a couple weeks ago on the Meremac River and just a few minutes into our voyage the warning horn sounds. The manual indicates this is either low oil warning or excessive heat due to blockage. Turned the boat around and drove it up on the trailer and all was well. Bought two flushing kits from my local boat shop to flush the engine as the oil level was fine. First was kit purchased the Mercury 820543A1kit, gets installed on the top of the block, flush for a minimum of 10 minutes and the rinse outlet nozzle. Did this, no issues. But I wanted to be able to start the engine in my driveway to check the overheating problem. So second, I bought Mercury 820573 plug (Dealer Kit). This gets installed at the bottom of the engine block, same directions. The difference being this allows enough water to start the engine. So I ran water thru the engine block for about 15 minutes but didn't start it because I had to recharge batteries first. Here is where things go wrong. Put everything back together and went to the river this morning. When I went to start the engine, it barely turned over and clanked like a rock was lodged in the pump. I can turn the cam shaft about 180 deg (from top of engine block with socket) but then it feels like the engine is seized. Reverse the direction and get another 180 deg and a hard stop. I removed inlet screen and the stator and cannot find any obstruction. I'm totally perplexed and asking for input on where else could there be a rock or debris that would stop the turning of the cam shaft? Any help is great appreciated.
