Battery/Electrical/Starter problem

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Well>Link I've still got some issues to work through. My original starter had been fine except for the switch. During the rebuild testing the starter didn't have enough power to turn it over according to the mechanic so he was using one of his until he gave it back to me. He also said my battery was shot and got me a new one. My father in law had a good working starter on a parts tractor of his he let me use so I hooked it up and all was well. (Other than it floods when starting after sitting. Think I have a bad float?) but anyway I was starting it and letting it run for 20 min or so each day to excercise it before spring and get all the kinks out. Never had an issue until I ran it out of gas. After that the starter wouldn't turn like it was locked up. I pulled it and it ran fine by itself. I reinstalled and everything was fine. I let it sit for three days, went back to start it and it was dead real dead. I jumped with antoher battery and with my car (running) and I could only get about a half a crank out of it. I went and got my mechanics starter and it worked fine. I started trying to test the electrical for a draw and this is what I found. Battery terminal to battery is 11-12v with engine running 13-14v. If I pull the negative cable off and go terminal to ground wire I get nothing with the ignition off and some current with it on. However if I let it set for a minute I get about a .5-2vspike for a brief moment with neg to neg and ignition off. I also get 30v AC current between terminals when the tractor is running.

Everything I've read tells me I have a bad diode on the alternator but wouldn't I see a draw with everything off if this was the case?

Before I go have my starter rebuilt is there any chance something in the electrical is burning them up?

This is a 12 volt system of course. Ifit is the diode can anyone tell me what I need to replace it with? (It's a three wire alternator two on top with battery cable on bottom.)

I did get the starter thing figured out kind of.

I guess even with jumpers directly on the battery cables (No battery connected) on the tractor and well seated to the terminals on a running car (Yes it is a negative ground) I just wasn't getting enough juice. Once I fully recharged the battery and put my replacement starter that had been working back in it cranked over just fine.

I've still got the leakage problem to figure out but after reading and learning more about this stuff I'm confused to an extent. When I look at the diagrams of how to convert to a 12 volt system the wiring doesn't look like mine. The diagrams have one of the two wires on top of the alt. going to the battery terminal on the alt and the other going to the ignition/coil. Mine has both the top two wires put together into the diode. Also the way the diode is wired it look as if it allows flow towards the alt no away from it? The stripe is on the alt side. When I test with an ohm meter it goes the other way but my mm is very cheap and I've read that cheap ones can have the direction of the flow reversed for ohm testing. I'm half thinking I should just put it back together the way it was (I've clipped out the diode) instead of trying to replace it and see if the problem repeats itself.
Sorry for being so stupid and lazy oh wait inexperienced. :)

Thanks!

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