Does my LT1042 have a voltage regulator?

apex944 · #1 06-18-2022, 03:24 PM

ironman · #2 06-18-2022, 04:45 PM

Well, yes and no....
Meaning you have no external voltage regulator, but your engine has an alternator under the flywheel that,
when the engine is running, puts out a fixed voltage solely designed to keep the battery charged.
And you only need the battery to start the engine. So that's your regulation.
The alternator also has separate windings that put out a separate voltage strictly for your headlights.
The spark for your spark plug is magneto generated, so you don't need any battery voltage for that.

apex944 · #3 06-18-2022, 08:59 PM

ok thank you for this explanation.
Alternators put our A/C so I should have been asking if my cub has a regulator/rectifier. I'm looking at the wiring diagram and I see the magneto output and two alternator outputs. Don't really understand where it is being rectified.

guyina4x4 · #4 06-18-2022, 11:18 PM

Yes it has a voltage regulator.
On your engine it's usually mounted right by the starter, on the engine block. Held on with 2 bolts and has a 3 wire plug.

ironman · #5 06-19-2022, 09:42 AM

Quote:

Originally Posted by guyina4x4

Yes it has a voltage regulator.
On your engine it's usually mounted right by the starter, on the engine block. Held on with 2 bolts and has a 3 wire plug.

Apologies, guyina4x4 is correct. I had model numbers confused.
Part #9 in drawing...

apex944 · #6 06-19-2022, 01:12 PM

Well you are forgiven for being confused given the mish mash of parts they threw on these things. In fact mine I believe has been re-powered. It has a Briggs Intek 17hp engine instead of the Kohlers they are listed as coming with.

I see the wiring changes color about 6" from the engine and the connectors have electrical tape on them so its almost definitely not original.

Will look for that regulator again today. Although I looked earlier where you described.

ironman · #7 06-19-2022, 02:31 PM

Well with a Briggs, depending on the alternator it came with, we could be back to maybe you don't have a voltage regulator.
The drawing I posted was for a Kohler.

If you have trouble falling asleep and need something to lull you, read this....
http://www.smallenginesuppliers.com/...xplanation.pdf

apex944 · #8 06-19-2022, 04:31 PM

LOL ok I like that doc. will definitely read it over.
OK you guys have been extremely helpful. Thank you.

The reason I started me looking at all the wiring was that the PTO clutch has died. And judging from the look of the electrical connector I'd say it was drawing a lot of current.

How would I go about determining if a Cub Cadet PTO will fit on this Briggs output shaft? I dont see any part #s on the PTO. Might have to ruin my Monday and tear it apart ;(

PS - still haven't seen anything that looks like a Rectifier. So I'm thinking this has none.

ironman · #9 06-19-2022, 05:45 PM

I can guarantee that you don't have one because I can see the red and black leads coming from your alternator, behind the dipstick tube. So if you look at the document link that I posted, page 2, top left, dual circuit is what you got.

Here's your problem:
That setup is usually on tractors that have manual pto's and no big draw electrical stuff (i.e. electric pto). It's just good enough to keep the batterey charged. And the a.c. windings can do the headlights as bright as candles. It can only provide 3 amps and most pto's will draw somewhere north of 10 amps when you operate it. So esentially, in yourcase, the pto is getting all it's juice from the battery and not the charging system. Meaning if you mow for an extended period you will eventually have a dead battery. The mower will continue to run, but the pto may disengage,

All that being said, from your pictures I would suspect that the melted connector is where your problem lies. Take it apart and inspect the terminals, and check that you are getting voltage on the blue wire. Also, unless your wiring system has been cobbled, there are safety switches that the pto operates thru. They cause problems too.

apex944 · #10 06-19-2022, 09:51 PM

I have no lights anymore. Must have fallen apart years ago. I have the light leads shrink wrapped and disconnected.

The PTO wont engage at all anymore. Started to intermittently disengage whenever I got into the tall grass. Now it will not engage at all. (Even with a fully charged (new) battery).

I believe the connector recently melted as a result of pulling too many amps through the circuit? Perhaps due to my excessive loading of the clutch when I stalled the blades in the tall grass (~3 feet tall) ... but that's just a theory. Oh and I also hit a few roots that stopped the blades dead. When I pulled the connector apart today it appeared to still have a good connection. I'll need a new connector now or I may just crimp the wires together.

With the ignition on, PTO switch engaged, and engine not running I have 12.6v at the blue wire.

Just did a test start with the repaired wiring. PTO still dead.

Update: "there are safety switches" Just read about the Reverse Safety Switch at the top of the transmission where the wires are fastened to the linkage! So much for American ingenuity.
I'll take a look at this in the AM.

Thanks again for all your guidance. Very helpful!