I was out on the boat this past weekend and took it for a couple hour ride. There was a fair amount of chop at times so it underwent some pounding but nothing I would consider excessive. At one point, I felt as though the power reduced but the throttle seemed responsive so I continued on. When I returned and was preparing to moor, I turned off the engine. Had to quickly restart due to heavy current and my dog getting in my way of grabbing the pick up buoy. Unfortunately, it wouldn't start. The engine was cranking but it wouldn't fire/turn-over. I tried repeatedly, even let her sit a few hours after mooring but same issue.
Towed the boat to the boat ramp and trailered her home last night. This morning, after reading some of the service manual I decided to see if perhaps it was something simple like a fuse so I opened the engine hatch, hooked up the hose to flush her while I was poking around and proceeded to check the engine fuses; all were fine with the exception of perhaps one of them being "loose" or not properly seated. I proceeded to unplug/plug some of the wiring, etc. but didn't really know what I was looking for other than something not being right. Didn't find anything that jumped out at me so I decided to try and crank her up. Low and behold, she turned over and started.
Now, I don't know if I'm paranoid but something didn't sound right. This motor was never quiet with the deck open and the storage bin removed but it seemed as though something was "clunking around. I recall reading here about issues with the air compressor. In troubleshooting yesterday I did actually swap out the belt since in the past that had been my source of trouble but honestly the existing belt seemed perfectly fine. I did notice, however, that one of the pulleys seemed wobbly/loose. There are four "pulleys" if you will, the main flywheel, the tensioner, another larger pulley and a smaller one. I am referring not to the flywheel but the other larger pulley.
I'm brining her in to get checked out because I don't want to risk running it and end up with some major damage.
Any thoughts in the meantime; sound similar to anyone else with the same engine (Mercury Optimax 250 DFI)?