kubota mini-ex elecrical system

My KH65 was running fine this morning, shut it off and when I went to restart it the electrical system was completely dead. No power to the ignition switch, the fuse panel or the batt post of the alternator. I "back doored" it by running a jumper wire to the fuse panel, this energized the whole system and it runs and everything has juice (15.5-16 volts...yikes!). When I turn the key off and back on the system is dead again until I back door it again. Ditto if I leave the key on and kill it with the throttle and want to restart it. Is there a master fuse? A wiring diagram would be nice, but I can't find any such thing. Help!

If it has one of the "master switches" that is actuated by the key switch, it sounds to me like you've got a blown diode somewhere. Typically you've got a hot wire to the ignition switch, and a diode that allows just the coil on the master switch to ground until the ignition switch is turned to the on position. In the on position it powers the coil in the master switch pulling it in to ground the entire system.

One way to check to see it this is the problem is to pull a ground wire directly from the ground on the battery and use it as a ground to see if you have power at the hit wire going to the ignition switch. If you have power at the hot wire using the ground directly to the battery, but not to the machine's frame when the ignition switch is on, then it pretty much has to be a diode blown somewhere. The ones I've seen are usually made into a plug that simply plugs into a mating plug on the harness somewhere. Where though is anybodies guess without the manual as I've seen them everywhere from close to the switch itself to 'hidden' in the console beside the seat.

I've seen this problem on several different brands of equipment over the years and it may be the cause of your problem. Hopefully I've explained what to look for and/or check in a manner that you can understand. Unfortunately beyond throwing the idea out there I don't have a clue what else to tell you without being there to look at it.

Thanks Wayne. When I checked for power, I had my multimeter grounded to the battery so I guess I'm okay on that. What about a fusible link or master breaker?

I'm in the UK,all the Kubota's I come across usually have two 50 amp slow blow fuses in the battery compartment,they are usually red in colour,have a look in the battery box the US models maybe the same.
AJ

Figured it out. It had a fusible link poking out of the harness just below the alternator. It wasn't blown, the connectors had rotted away. It's such a pain to get to, I think I'll just replace it with a maxi-fuse in an easy to get to location.
What size fuse would you recommend for 10 ga. wire?

Duh. Perhaps a 50A slow blow would be about right. I think I'll put it in the battery compartment. Thanks guys.

Glad to hear you figured out the problem and thanks for posting what you found. Working on equipment for a living I always like to know what the cause of a problem is because I never know when I might run into the same situation myself at some point in the future.

You are dead on the original link was 50am . The breaker out of (or Like used on) larger semi trucks works well. You may not have anything ecxcept that worn connector. The KH series are all 20 + years old getting some age on it. Sold a world of the KH 38s they were great hoes. If you get a chance sit in the seat of one of the pilot oprated newer ones. Just unbleviable how the hydraulics have changed. Current model KUBOTA parts drawings are avl at KUBOTA.com but nothing on the older stuff.

I've got a Hitachi 120 ser3, so getting used to the old hydraulics on the Kubota is going to be tough. Wish I could switch it to pilot control but that's probably not feasible. I found a shop manual on CD out of Canada for cheap. I'll probably order it. I hate doing electrical without schematics.