D15 series 2 shuttle shift

Does it still have a genorator?   If it has a genorator it is probably still 12 volt positive ground the easiest way to tell would be to check the actual battery that was installed.   Always check the marking on the battery before hooking up a charger or jumper cables.   If it has a genorator I would polarize the generator when you install the new battery.

If it has points and condenser I would check the points in they look at all questionable I would pick up a set of points and condenser they are pretty cheap and you will need to replace them at some point anyway.

I would put some fuel in the tank shake the tractor and see what come out into the fuel bowl before running it into the carb if there is a mess in the tank it would be better to know before you plug up the carb. If good clean fuel flows out into the fuel bowl then I would think the fuel system is good.
Pull the oil bath air cleaner bottom clean it out and put fresh oil in checking the screens quickly to make sure nothing got in there. I would pull the air line to the carb until you know that the carb is working correctly. You don't want to run it without that air line hooked up but if the float is sticking gas will fill that line and can be a fire hazard if it backfires better to have it off while you are trying to learn the new tractor.
So with clean oil good coolant and a new battery I would try to start it if the starter turns it over half the battle is won.

You should be able to move the carb linkage. I would unhook the linkage from the carb and work it by hand the first time just to see if the motor will fire. Also try forcing air through the carb you should be able to blow through it if not you have a problem and need to take the carb apart and clean it. As to the air filter should have known I was thinking of my serries 1. With the serries 2 filter pull the filter check the cone where air goes into the filter and check the housing. My serries 2 air filter housing was rotted out and full of mud wasps.

7040 wrote: Thanks for the tips it is definitely a positive ground and definitely a generator. I do have a question how do I polarize the generator I have never done that

Use a jumper wire from the "BAT" terminal of the regulator the the "GEN" terminal.  Just a quick touch, do not connect them or hold them for a long time.

Thanks again lots of great info