Re: OMC Cobra v. Stringer outdrive?
If you have a large black rubber boot around the back of the drive and attached to the transom then you have a Stringer. Like mentioned, the stringer drive has three separate compartments, the intermediate (IM), the upper unit and the lower unit. The IM has a screw head plug at the top, take it out. On the side of the IM on the right, down kind of low on the IM is another screw head plug, remove it and oil will drain out. I would go to Wal-Mart, look in the marine section in automotive (could also be by the fishing supply) for a Quicksilver gear lube pump. It will make the job a lot easier and less messy. The pump is like eight bucks. Screw the pump nozzle in the lower drain hole and pump the fluid from the bottom to the top. This is how you do it to make sure no air gets trapped in the housing and not enough lube is added. When you start to see it at the top plug hole stop, I wouldn't pump it until it comes out the top but you probably can as you will lose a little when you take the nozzle off the side and quickly reinstall the plug. To help, install the top plug first, this should help hold the lube in the case so it will not drain out so fast when installing the lower plug.
The upper unit will have a plug/dipstick right in the center at the top. Loosen it and then look on the right side of the upper unit and you will see the drain head screw. Take it out and let it drain. Now you fill this just like you do with the IM (pump the fluid up through the drain hole). Pump it for a little while, not a lot, and reinstall the top drain plug/dipstick. It has a mark on it. You can ad some lube through the top if needed to top it off but it gets hard to determine the level as the dipstick will get covered in lube. You will have to wait a little while for it to drain into the housing. Then check again until you are at the right level. Then reinstall the dip stick at the top.
The lower has a drain head screw at the very bottom in the right and one at the top on the right. Take the top one out and then the bottom and let it drain. Again, fill from bottom drain. Fill until it just starts to come out the top. Put the top plug in, then unhook the pump and quickly put the lower drain plug in. The lower will have a magnet attached (part of the drain plug), check it for any metal debris. It will probably have a tiny amount of metal dust from normal gear wear. Clean it off before installing. I use Wal-Mart's Super Tech Marine High Viscosity 80W-90 lube. Works fine. If you get it, buy it in the quart bottle that looks like a standard quart of engine oil. The pump is made for this. If you get the large cylinder shaped jug the pump won't get all the oil out of it (the tube won't reach to the bottom).
Pump...
