Question for Sam Mac (others too!)
 

I too am having the dreaded 'ALT' indicator lighting up on my 1641. In the past it would come on when the PTO was engaged and then go out after running for a while. The last time I used the tractor the light was out but later the indicator light began to flicker and then came on solidly. Today I did the tests referenced in your quote to another member some time back. I got 28.2 (mostly, with some variation up to 28.8) volts at the yellow plug you mentioned. Close enough? This was with the engine running a bit below WOT. I know it's supposed to be 'AT' WOT but I kinda cringe to hear 'em scream like that, I usually run it about 3/4 throttle when mowing. I got nothing from the red wire coming from the VR so I'm assuming that's a failure and the VR needs to be replaced. Looking at the picture of the Kohler regulator in another of your posts on the same thread shows it marked with 41 403 09. Would that be the part number for the regulator? If not could you give me the number of the regulator to use for the conversion? Many thanks.

Darryl

Quote:
<< I'd check to see if you have about 30 volts AC at the plug to the VR. It's the square plug with the two red wires. Unplug it and put your test leads on the two pins inside the plug coming out from the engine. I'd also test to see if you have about 14 volts DC at the red wire on the existing regulator, it may be OK and you could have some other issue. Test before replacing stuff. If it turns out that your VR is bad you can use the leads from the old B&S VR just cut them at the green line in the pic, crimp on the spade connectors, I suggest that you use the insulated type. The yellow leads go to the outer terminals ant the red lead goes to the center. Think you will need a spacer to hold the VR away from the engine enough to clear the wiring. Make sure you have a good ground. >>

How many volts is the battery gettting? We aren't concerned with what the alternator is putting out at this point. You do know when you tested it that it is AC voltage before the v-reg right? You did test with the meter set to AC?

Stop worrying about the motor "screaming". Don't be chicken, they have a governor, your not hurting it. Rev that thing up!!! Mowing, testing, whatever... It's a tractor, they're made to run that fast.

Thanks, Jon. Yes I had the meter (Fluke 12) set for AC to test alt. but your question made me wonder if I'd remembered to reset it to DC to test the red VR output lead which showed zero. So tonight I re-ran the tests. Meter on AC, the stator leads showed a pretty steady 29v. Hopefully that's good enough. Then with the stator wires reconnected and meter set to DC the red VR output showed zero. With all wires connected and engine at WOT, meter set to DC, the voltage across the battery cables at the battery was 17v. Engaged mower deck and it dropped to 15.3 ( or .4 ). No ALT light on. Too high I believe. Re-did VR tests and went back to the battery leads. This time voltage was 12.5xx at the battery at WOT. Engaged the deck and voltage dropped to 12.4xx . Subsequent tests showed a slow small incremental voltage drop to 12.38, then 12.37 Around this point the ALT light came on. I stopped here, but I suspect the voltage would have continued it's slow drop.

With the high initial 17 volts and later low (and falling) volts I'm thinking the VR isn't working correctly. Sam Mac said in a post some time back that the stator voltage should be 'around 30v. AC' so hopefully 29 is OK. Any further testing to do before I try the Kohler VR? If it's time to try the VR which one should I get?

Thanks for all your help. I'm obviously electrically challenged.

Darryl

Your tests were good. The initial test that yielded 17V though..... then later no apparent charging makes me wonder if the VR is getting good ground. I suggest either cleaning it's mounting point, or running a wire from the mounting bolt to the engine block or frame. If it still continues to intermittently charge/overcharge, then yes, replace it. I'm pretty sure Sam went to the Kohler VR. Part # KH-25-755-03.

Many thanks! I'll make sure the VR is well-grounded and see what happens. If it's a no go I'll do the conversion. I appreciate your help!

Your welcome, good luck! :beerchug: