Questions about a Merc 20

Hey everyone,
I have been reading this site for a few months now, and recently bought a boat that I want to get fixed up a bit. Its a 73 duracraft 14' v, with a 73 Mercury 200 (20hp). It has a starter on it that I was able to get working with some jumper cables. The boat didn't come with the cable that goes to the battery, and there is no starter button on the motor. There is a cable hook up on the side of the motor though. Just wondering if anyone knows were I could pick up one of these cables, and if these type of motors charge the battery while running. If they dont I prob wouldn't bother with the starter, its not that hard to pull over, it would just be nice to charge it up when I drain it with the trolling motor.

Question 2, I tried to change the gear lube, but when I pumped in the new stuff I couldnt get any to come out of the vent hole, and the pump just built up pressure in the bottle after I got maybe half a quart in?

Any thoughts would be a big help, thanks!

I have a 1979 with a plug on the side also & couldn't find one so I made one myself.My rectifier is mounted on the back of the motor.Look for yours to see if it has a charging system.Those motors with a plug on the side use remote controls.
Make sure your filling & venting the right holes.I didn't think mine used that much.(half quart)

How did you make it? Does your vent hole have a horizontal screw next it?

The vent screw is the smaller one & the other screw by it is the flushing hole for the waterpump.The screw for filling is at the bottom,same side as the vent but at the bottom just below the line of the prop shaft.
Sound like you where putting oil into the water pump.Thought half quart sounded like a bit. [-X
I made my plug out of copper tubing & some ingenuity.I just used the + & - post on the plug that I made & ran another wire out of the motor for the start & kill switch which I have mounted on my transom corner.