Hey all. Need a little help here. I've got a 1995 Mercruiser 4.3 LX. Getting a late start with the boating season. Changed the crank case oil and a few other little projects. Here's where I went wrong.
When I pulled the cylinder block drain plugs when I parked it, I had issues with the port side plug. Namely, the brass sleeve that threads in to the block and the actual plug threads in to came out of the block. I wasn't too worried about it at the time, since either way the water drained out. Of course, I didn't have the forethought to reinstall the plugs after draining the water.
After hours and hours of trying, I couldn't get the sleeve to thread back in to the block today. I think there must be some rust build up in the there. I couldn't find any good way to clean the threads (no wire brushes small enough, no thread brushes available anywhere). I think I may have to chase the threads with a tap, but it seems to be a weird size. I can probably find a properly sized tap to "borrow" from work. Just wanted to hear everyone's take on it here before I jump in to it. I'd hate to run a tap into the block and majorly screw something up.
It also seems that the hole seems further back and higher up on the block than I remember. It's towards the aft end of the block, directly above the oil filter location.
Here's a closeup of the threads:
There's some rust staining coming from a hole in the block directly below the drain plug on the exhaust manifolds. The hole seems to be plugged, too small, and not threaded, so I'm fairly sure it's not the correct location.