Yamaha outboard engine 4LK 6EO l 323627 HOW DO i CHANGE OIL IN

You do not have to remove the top plug. Just loosen it enough to allow oil to drain out the bottom. Same with filling, the top plug just has to be loose enough for air to escape as you pump oil in from the bottom. When the oil starts to seep out the top, stop pumping, close the top port screw and then put the bottom screw plug in. With the top port closed there should be enough vacuum created you shouldn't loose more than a few drops while installing the bottom plug. Please do not over fill the gear case, it needs a little air space. Also, try to avoid over pressurizing the gear case while testing, it only takes a couple pounds to identify a leak and not much more to create one. Another thing, change your gear oil in the fall before freeze up. If you store your outboard outside all winter and there is a little water emulsified in the gear oil, it will separate and freeze,, I have seen more than a few cracked gear cases from this alone.

To change fluid,take out the bottom plug;should be a flat head screwdriver fitting place something to catch old fluid under the lower unit,then take out top plug,it should drain right out... then from the bottom... fill the lower unit till fluid starts to come out of the top hole then put bottom plug back in, then top plug back in and your good to go..when you have the plugs out check the seals on the plugs and replace if needed...that will insure no water can get in..as far as the fuel mixture you can google that info