Craftsman Riding Mower Electrical Problem

[dennis]

I have a Craftsman DLT riding mower, Model 917.273451, with a 25 HP Briggs and Stratton twin cylinder engine.....Model 446777, Type 0246-E1, Code 021212YG01545. The ignition switch has 4 poles. Stop, Lights, Ignition, Start. When it is running, if I turn the switch to Lights, the engine will kill. I thought it was a bad ignition switch. However, if I unplug the lights, it will run when the switch is in the Lights postion. With the lights unplugged and the switch in the Ignition position, the ammeter shows good charging. If I turn the switch to the Lights postion, it continues to run, but the ammeter drops. Any help would be appreciated.

[KE4AVB]

Here is the wiring schematic for 917.273451. Your either have a short in the lighting circuit or possibly a bad ignition switch. The ignition is a Delta 6900-47. You should find "47" embossed into it. According to the wiring schematic there is nothing on the "L" terminal other than the lighting circuit. Ohm out chart for the switch is in the lower left of the diagram.

I would go ahead and isolate the "L" terminal of the switch by removing the terminal from the connector. Then if you still have an amp drop, it got to related to the ignition I would think.

[dennis]

Thanks, KE4AVB. I will try that.

[hanz63]

Yep. Had had a couple that were no cranks over the years that the owner clipped the damaged headlight harness not knowing that the two grounds that were joined at the terminal could not be separated.

[dennis]

Update.....checked complete lighting circuit for shorts and continuity, and could not find any shorts or open circuits. All terminals were surprisingly clean. Put everything back together, and now it runs with ignition switch in "lights" position with lights on, without killing. Go figure. If it happens again, after bouncing around a little, I will replace ignition switch. Thanks for help.

[KE4AVB]

Did you check the wires for bare spots?

[Arkie]

Subject: erratic acting lawn tractor ignition switches

I've seen lawn tractor ignition switches, especially the ones that set outside exposed to weather and the switch almost vertical on the dash (keyway pointed up so as to catch water) get water inside and get rust scale inside and cause electrical leakage across the terminals internally.
They will usually get erratic acting at first and spraying a contact cleaner into the key slot may result in a temporary fix.
The fix is a new replacement switch. You have to keep a heads up and use the CORRECT PART NUMBER for a replacement ignition switch. In this instance ONE SIZE DOES NOT FIT ALL electrically internally even though the terminal arrangement on the rear of the REPLACEMENT switch looks SAME AND THE ELECTRICAL wiring PLUG WILL FIT.

[dennis]

KE4AVB....I did everywhere the wire was exposed, but not in the conduit.

[KE4AVB]

The switch used is a Delta 6900-47 switch. Several different graphic versions. Four position.

[dennis]

Yep, that is what is on it. Thanks.