TEA-20 Furgy Melted wiring harness fuse keeps blowing

Masey Furgeson TEA-20
12v Positivly grounded

I had initial issue not getting spark from the plugs so i replaced spark plugs and still same issue.
I noticed coming from the start swtich (solinoid) there was a blown inline fuse i could not replace this fuse out in the middle of knowhere so i thought i
would just wire it togeather and pray it would work....I tried to start tractor and then half the wire harness melted....
I have now tried to eleminate each part by remove it, the wiring harness now has the AMP guage, charge indicator (red light) and ignition key switch all removed and just wired togeather.
When i connect the ground to the battery BAMM same thing happens big sparks and the wires melt....
I removed ground and sanded the connections down and cleaned them well, tested with multimeter and all seems good.

I have no clue and im far from anyone that can assist me all i got is the internet and my shed, options?
should i wire it with heavy guage wire... i really got no clue why would they design something like this i got no idea?
If i dont slash soon im going to get over run with snakes !!

Thanks in advance,
Will keep tinkering

Wiring Diagram:
http://www.agriline.co.za/tractorparts/series_TE/images/tea20wiring.jpg
http://fergusontractors.org/nfs/wp-content/uploads/electrical/TE-TEA-20-6V-12V.pdf

Links on same issue:
http://www.tractorbynet.com/forums/massey-ferguson-owning-operating/274784-265-massey-blowing-fuse.html
https://www.tractorforum.com/threads/massey-ferguson-to-20.23867/
http://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=ferg&th=115851


Image of ground going to starter bolt not like mine, mine goes to back of dash:
http://forums.yesterdaystractors.com/photos/mvphoto9497.jpg


Wiring Harness:
http://v2.ca-en.sparex.com/ItemDetails/ItemDetails.aspx?ItemNumber=67037

Can i somehow get jumpers and connect the battery directly to starter or distributor or something bypass all that crap ?? Im not to good at this but keen to learn.

Sorry to keep replying to same post it will not let me edit it and i keep thinking of things to add, can anyone tell me what i should do to bypass everything, how can i wire battery up to just "start" with the less parts to the system thats needed. Its clear i dont fully understand but im keen to learn from what i can tell the starter and the distributer both need negative power and the positive goes to ground, so if i connect jumpers from positive on battery to a part of metal on tractor then from negative on battery to starter and negative on bnattery to distributer cap im good to go ??? Sorry if i sound silly or ignorant.

You have to find your DEAD SHORT or you
will keep burning up things. A multi meter
will be of the greatest help to you. The
fuse did save your harness the first time.

Agree with the above and don't bypass the fuse or the whole tractor might end up like your wireing harness. Find the short circuit!

Could be starter bolt tightened without holding nut under cable which allows contact inside starter to turn and short. Test by disconnecting starter cable and then touch jumper cables to
starter and battery.

1.Unless it has been modified, most likely place for fuse is feeding light circuit, but could be something else.

2. Get a 12 volt lamp. Momentarily connect lamp between your disconnected ground cable and + battery post. If lamp lights up you have a short circuit somewhere. Start disconnecting circuits (switch, ignition, alternator, etc.) each time connecting lamp again. When lamp stops lighting you have found your shorted circuit.

3. With fried wiring harness you may have several other short circuits to deal with.

4. Original short circuit was probably a wire that was pinched between 2 metal pieces, rubbing on frame or a hot manifold.

5. If it were mine I would do a complete rewire, and doing the lamp test each time I connect a wire.

i remember a wiring harness burn out on a MF 575 a long time ago and that was caused by the battery clamp touching the positive terminal

something else I have just thought about and that is could the contact points in the control box be stuck and is supplying power to the dynamo making it an electric motor but it cannot turn because of fanbelt

First thing to do is remove the starter and determine whether it works properly by connecting it to a battery . Support it well or clamp it down before you do .
Second , remove the gear stick starter switch and make sure this works properly and isn't corroded or burnt . These are really the only two things apart from battery leads that carry enough current to cook things like you've described .

Console, I agree with Charles.
Something changed from the last time the tractor ran properly. It created a short then you inline fuse blew and stopped major damage.
The two main culprits will be starter connection bolt and gearbox starter.
Let us all know how you progress.

All the advice given so far is good stuff... but something keeps popping out at me in the first post... 12 volts are rarely positive ground/earth.... 6 volt yeah... was it connected like this when it was running good?

I don't know if this is the case with the U.S. made TO Tony , all UK TEA 20 tractors built after the last months of 1951 left the factory with 12 volt positive to earth wiring.

In reply to Charles: All TO20 and TO30 were 6 volt. The TO35 started as 6 volt then at S/N 161250 in 1955 they became 12 volt.