Re: Drain Plugs 1990 4.3l OMC
And in addition to the 4 on the engine, one on the ps cooler...there are 3 on the pivot housing, the part of the transom mount that the drive bolts to. There are 2 on one side and 1 on the other, you have to tilt it up to see both on the side with 2, and yes water does come out of these sometimes, not every time I removed them, but most of the time. Make sure you use a big screw or small screwdriver to clean out any big rust flakes that may be blocking the drains esp on the manifolds and engine block. Also make sure you remove the big hose at the front of the engine, at the bottom end, that lets the front water pump drain and also drains part of the front section of the block/heads/intake manifold. Finally, disconnect the hose that comes from the transom up to the thermo housing (the ps cooler is in line with this hose), point it down in the bilge and let it drain. This will probably drain the cooler too, but I always remove the cooler drain just in case. I then fill that hose with AF till its full, then reconnect. You may see some AF come out the water intakes on the drive, this means it got all through the impeller housing which is good. I reconnect the bottom end of big hose on the front of the engine, then pour some AF in till it comes out the block drains. I replace the drains (put a little grease on the threads) and fill the engine thru the top end of that hose, till AF comes out the thermo outlet. Then re-connect the top of the hose. Do the same with the manifolds, disconnect the hoses at the thermo housing, then pour some AF in till it comes out the drains, then replace the drain plug and fill it till you hear it come out the exhaust (USE NO TOX AF!!) Re connect the hoses. Some people like to just bump the starter a bit to make sure AF gets into the impeller housing. I remove the drive for the winter and check to make sure there is no water in the driveshaft bellows.
