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Alternator/charging system questions for model 917 254410

5800 Views 10 Replies 4 Participants Last post by  ldlittsen
Hello Guys, I have several questions regarding the alternator/ charging system on an old GT 18 I drug home the other day. 917 254410 To begin with the wiring was a total NIGHTMARE. The ignition switch was replaced with a single toggle switch. (with the switch in the down position it was off, center position it was on, and pushing up on the switch would engage the starter) There were wires going nowhere, wires cut, spliced, etc,etc. I was told that the tractor had been sitting for several years. It has an 18 H.P. Briggs horizonal shaft engine. I cleaned it up and got it running (Runs fine) and thought I would sort out the wiring. What a mess. I decided to eleminate the wiring and start from square one. I wired a "Kill " switch directly off the mag for the on/off. Then I wired a push button switch to activate the solenoid and that works fine. My first question is how can I do a test on the alternator? The tractor has 2 black wires coming from the alt. and into a small plastic box which is the regulator? And out of the regulator is one red wire with a white stripe. What do I need to do to check the alternator? And my second question is if the alt. checks out OK what wiring do I need to do to so that it will charge the battery? I have found the wiring schematic but being as Electrically challenged as I am I cant figure out how to wire it so It will keep the batt. charged, and run the headlights. I was hoping that You Guys could help me figure this out. Thanks in advance, Litz
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Did a search on "917.254410 electrical diagram" and it looks line there are at least 4 other members looking for this too. That's all I have.
Thanks for the reply Guys, I'm trying to figure out how to test the alternator, and if it test's good how I can wire it so it charges the battery. The manuals will help. Thanks, Litz
easy-peasy, ldlittsen. Two black wires into yellow plug from alternator are AC voltage. Yellow wires carry AC into the voltage regulator. Single red wire out of the regulator should read 13-14VDC, depending upon state of battery charge and engine rpm. Run that red wire directly to the battery, via a fuse or circuit breaker, and to any accessories, IE lights, fuel solenoid, etc...

Seth K. Pyle
Thanks for the reply Pylek I didn't think it would be as simple as that! Thanks again, Litz
I ran a wire from the red wire that comes from the regulator to an amp guage, and then to the battery and it shows that there is nothing coming from the regulator so I assume that the reg. is bad? Can I use a test light to check either of the 2 wires that come from the alt. to see if it is working? Sorry for all the questions, but I know absolutely nothing about how the charging system works on these tractors. Also can I pick up another type of regulator at an auto parts store or does it have to come from sears? Thanks in advance again, Litz
If you have a Voltage regulator, then there should be 2 yellow wires that "INPUT" to the VR.
There should be somewhere between 28 to 40+ Volts AC between the YELLOW wires. I guess if your test light filament is still intact, there's no output. If it blows the filament, there is some output greater than 12V:fing20:

A better way would be to use a Voltmeter on the AC range.
Thanks for the info Bill. The 2 wires going into the input side of the reg. are black, and the single output wire is red with a white stripe. I will use a voltmeter between the 2 black wires and see if it shows anything. Thanks again, Litz
I tested the voltage with a volt meter and it showed 39 volts A.C. so the alt is OK. Now hopfully all I have to do now is try and find a place that I can order a regulator. Thx Guys, Litz
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