Re: 1989 OMC Cobra Lower Unit Oil
I think you can still order original OMC shop manuals from OMC dealers (ones currently selling Johnson/Evinrude), I got one for my 88 4.3 Cobra last summer for about 35 or so, it is very well written and illustrated, much better than aftermarket. As others said you have to do this right or you will toast the upper gear set (~$1000 to replace!). To drain, remove the top plug (at the very top of the sterndrive). Then place the plug back in the opening but do not screw it in. Next drain from the bottom plug in the lower unit. After it drains, replace the bottom plug and remove the middle plug. Attach the pump to a bottle of OMC hi-vis gear oil, and screw the pump into the middle plug. Now pump slowly (to avoid air bubbles) until you get about 2qts in it. Check the level on the top plug (it had a dipstick built into it. When it reads full, screw it in, then quickly remove the pump and replace the middle plug. Unscrew the top plug again, check the level. It may take a while for the air bubbles to get to the top. Let it sit overnight before running it, check it again with the top plug. If it's full run the engine on the muffs for a few minutes, stop and check it again.<br />NOTE: when I say middle plug, on the lower unit (where the prop is) there are 2 plugs, the fill plug is the upper of these 2. You may see a screw head (used to be covered by a Cobra medallion or a rubber plug) in the side of the upper unit, DO NOT take that one out if you do the retainer in side will fall down and you will have to remove the sterndrive and take it apart to get it out!! BTW, that screw has to be watertight or the impeller in the upper unit may suck air instead of water. Sorry for the long winded post.
