Kubota T1870 Blowing main fuse

[Marbarian]

Trying to identify and resolve intermittent Fuse blows incident. Rewired the tractor removing all safety switches. Mowed the grass for 15 mins and problem continued. Went a little further to replace carb valve wire and coil wire (Magneto). Same problem, as soon as you turn the key to run the fuse blows.

Could the actual rectifier or Carb Valve cause this? Ordered new Coils, but don't see how they could be source of the problem.

Any advice is appreciated...

 

[jaxs]

You obviously have a wiring diagram and which fuses control what so I have some questions.
Are you certain blown fuses are correct amp rated?
Are you certain it is MAIN FUSE that blows. that is to say 12 volts isn't available to any other fuses after this fuse blows?

Does this carb valve which you suspect have it's own branch fuse? If it does, that fuse should blow since it would be lower amp rate than main. I suspect a short between switch, main fuse and/or fuse box. Pull all fuses and substitute a 12 volt light for main fuse. If bulb lights your problem is before fuse box. Move wires to see if bulb gos off when short has been temporarly interupted.

 

[Marbarian]

Thanks for the reply,

I only have one fuse now, inline with the battery (12v) and the Ign switch. I completely removed the entire wiring harness and wired the 5 leads from the ignition switch to only control the engine.

I do have a service manual for the mower.

Upon further tests, I suspect the switch, the previous owner bought a new tractor and gave me this one. He provided a new switch which I am using, and of course I checked the switch to ensure proper operation:

Ignition Switch key positions
Off = Ground to Magneto
On = Battery to Carb valve (Additionally Grnd to Mag disconnect)
Start = Battery to Solenoid and Carb Valve

But, I don't know where he got this switch( could be a $19 one at Tractor supply), and after unplugging the Carb and everything else I still blew a fuse... So, it has to be the switch. Ordered a new from Kubota and will report.

62 Years old and I've never bought a new tractor(Hillbilly upbringing), this Menace may change that. Of course when it's running It seems like a very nice mower.

-Patiently watching the grass grow

 

[Russell King]

Can you just supply power to whatever needs it to run (bypass switch completely) and use a starter switch to crank the engine (Or just short positive cable to the solenoid spade)? That way you could mow until the new switch arrives.

Of course you need to know how to stop it from running when you need to turn it off (but you seem capable of that).

 

[jaxs]

"-Patiently watching the grass grow"
Mom said there's usually a silver lining if we look for it. I guess that means used tractors can teach us patience. If it's any consolation , never a month gos by that someone doesn't say their new tractor spent more time in dealers shop than at their house since they bought it.

Seriously, can't you temporarily use a universal switch ( basically hot wire it) until the replacement arrives?

 

[jaxs]

Can you just supply power to whatever needs it to run (bypass switch completely) and use a starter switch to crank the engine (Or just short positive cable to the solenoid spade)? That way you could mow until the new switch arrives.

Of course you need to know how to stop it from running when you need to turn it off (but you seem capable of that).

Ahhaa so that's what they mean by run-a-way diesel engines.