B6200 blowing 15 amp fuse

[lanschuetz]

Been working on this for a couple of weeks now, and am increasingly baffled.....

A couple of weeks ago the tractor stopped while attempting to mow heavy, wet grass. No big deal, that happens. But this time the battery was dead. Also no big deal, it was installed in August 2003! Put in new battery, the 15 amp fuse blows after the wires to/from it get incredibly hot.

So, after buying a bunch of 15 amp fuses, I began the process of trying to figure out what is wrong. The tractor does not have to be running for this fuse to heat up and then burn out. I took the voltage regulator out of the circuit - even replaced it - and the fuse still blows. Disconnected the voltage regulator, 4 way flashers (they aren't on that fuse), idiot lights and fuel sender. Fuse still blows. If you turn the lights on, the failure happens more quickly, but the result is the same.

I don't think it's the "dynamo" as it happens with the tractor not running. I can run the tractor without this fuse - though I have no idiot lights, no fuel gauge and no lights.

I've walked all the wires, re-cleaned the battery terminals, checked the ground (negative lead from the battery) and have found nothing obvious. This is some kind of current drain, but I don't know where else to look. I guess I can re-wire the entire beast, but it just shouldn't be that hard. Grrrr.

Before I go buy a new ignition switch or some other expensive part, I'm willing to listen to good ideas.

Other details - this one has the battery safety switch (a big red key under the left side of the panel), work lights, but no horn.

I don't think it adequately charges without this fuse in (though it does run and otherwise seems fine). Help?

 

[Soundguy]

put a lamp in line in place of the fuse. it will light up if there is a sufficient draw ( we can assume there is at least a 15a draw! )

NOW

start disconnecting lines , working back toward the battery ( end at the battery. )

when you disconnect something that makes the light go out. you found the offending part.

a little labor intensive. but GUARANTEED to find it!

 

[lanschuetz]

Thanks for this brilliant suggestion. It worked and I found the problem.

I ended up ruling out everything. At that point I was about to take out the ignition switch when I noted that the switch had rotated about 1/2 in it's socket. This was enough to allow the boot from the 12v input to make contact with the boot from the fuel gauge lead. Over time they were making enough contact (though the fuel sensor - which is a resister) to cause the current drain. A nightmare to find, but now we're good.

 

[Soundguy]

good deal.

it's a labor intensive method. but it rarely fails to yeild a definative answer.

 

[lanschuetz]

And, son of a gun, "it's back!"

Fuel gauge had moisture inside when I started. Mowed 45 minutes, fuse popped. Finished mowing (don't really need electricity for
mowing) put in new fuse and all was good.

Who wants to bet - with me - that it intermittently does it again next time or two that I mow? Dagnab it.

Seriously thinking about taking all the wiring off the fuel gauge. It's about as accurate as one of those wet rope weather forecaster
things and seems to just live to make life difficult

 

[GPintheMitten]

I had a B6200 once. The ignition switch would turn in the socket. I replaced the switch. I agree that the fuel Guage isn't real important but I would replace the switch.

 

[skyhook]

When the ignition switch touched the fuel gauge, it may have shorted something out in it.
Disconnect it and see if the problem goes away, replace the gauge if it does.