Briggs Alternator Question

[bob]

I have a Briggs and Stratton 42270 twin cylinder engine with low voltage at the stator. This is the stator with one diode for battery and ac for the lights. I am reading about 9 volts on both sides and disconnected from battery and lights. Is this possible to be working but with a low voltage and what would cause this

Blair

[bgsengine]

sounds like magnets came loose from flywheel - the internal magnets inside the flywheel.

[bluemower]

you did not state how you performed the test.

this is the Dual Circuit. There is a black wire and a red wire. the connector is white. Small magnets were specified with the dual circuit.
The service manual has a specific method for testing. At 3600 rpm, the AC should be around 14 volts. DC should deliver 2 amps to a fully charged battery. If the battery is low, expect 3 - 4 amps. Most of these engines were governed to 3200 rpm, so the out put will be less.

If the proper test was performed and the output is still low, here are some ideas
1. As mentioned, a problem with the magnets may have occurred
2. Corrosion may have formed around the stator and mounting screws
3. Battery may have previously been installed backwards and some coils in the stator were damaged.
4. problems with the equipment electrical system may exist. As examples, a
pinched wire may be drawing some voltage. Corrosion on a fuse holder may reduce amperage. A ground wire connection may affect output.

[KE4AVB]

I might add here that each wire of the dual stator must check in reference to ground and not across each other or you will get funky readings. The black wire is pure AC and the red with the diode will read AC and DC because it is a half-wave rectified circuit. The battery is used as a very large capacitor to smooth out the half-wave rectified DC signal. IT will still have some AC ripple but nothing that will hurt things. Just got to make sure the diode is good and that stator windings are not shorted. Plus as mention that all the magnets are in place.

[bob]

Removed flywheel and checked magnets, seemed to be solid. Checked resistance of stator with another one I had and was the same. Cleaned up all the grounds for stator and now have my 12 volts back

[RoyM]