1641 Fuse Blown, won't run, not ignition switch.
 

So I was installing my mower deck, brake pedal was in the lock position and the tractor was running. I was moving the hydrostatic up and down and then the tractor shut off. I found that I blew the fuse that goes from ignition switch to the starter solenoid. The last time I had an issue with this my headlight was lying on the exhaust shield, the tractor would run but when I would move the key back to lights it would blow the fuse. This is not what is happening now, the tractor will start for a few seconds, the fuse will be blown and the black side of the wire going to the ignition switch will be very hot.
I cannot find any wire that is grounding out anywhere, I tested the ignition switch and thought it was bad but the new switch is doing the same thing.
I left the key and run without a fuse and used my power probe to engage the solenoid which started the tractor but it would die after about 5 seconds.
I'm hoping someone has an idea of what is going on.

Do you have a schematic for your 1641?

It looks like the fuse is bypassed in the "start" position so that explains why it blows soon after you are in the "run" position. Yep, you have a short somewhere.

Obviously you have a short. Time to dig out the DVM and measure between Chassis Ground and the Ignition Switch "R" terminal (Red/White) wire, engine off. There should NO resistance. If there is, you will have to trace down what is on that circuit causing your issue.

Thats great but how exactly would I complete this task, youtube tutorial?

Thanks

Do you own or have access to a digital multi-meter, an analog multi-meter, or a voltage test light??

Check the tail light connectors as one may be loose, worn and grounding on the frame BTDT

I have all of those and a power probe, have the tools, just not much knowledge when it comes to electronics.

So I'm having a really hard time, if I unplug the ignition switch and I run a jumper from the S terminal straight to the battery the tractor will start and run but for only about 5 seconds and then dies. If I run a jumper from R to battery, the starter actually moves a little bit, is that telling me there's a short between s&r somewhere in the mess of wires?

If you look at the bottom of the bowl of your carburetor, you will see a plug with two wires attached to a thing called a fuel solenoid. The fuel solenoid's purpose is to stop fuel from flowing through the main jet of the carb when you shut the key off. The idea being, to prevent backfires caused by raw fuel being sucked thru a non running engine and exploding in a hot muffler.
In normal operation, when you turn your key to the start and/or run position, 12 volts is delivered to the fuel solenoid and it stays open allowing normal fuel flow until you turn the key to off.
When you have the key switch unplugged, there is no 12 volts applied to the fuel solenoid. Therefore when you jump the starter solenoid, the engine fires and dies because the fuel solenoid has remained closed and the engine is not getting enough gas.

Not clear on what you mean by starter "moves a little bit" , but if you are cleanly applying 12 volts only to the "R" terminal of the plug, no the starter should not move.

Yes so if I apply 12 volts to the R terminal, the starter tries to spin and the wire grounds out onto the battery terminal.