Stator repair

[Jim]

I have a Craftsman riding lawn mower that never charges the battery. I took some of the shrink wrap off of the stator wiring and the diode simply turned to dust. I was told at the dealer that since the diode was bad the stator was probably bad. So my choice seems to be to either replace the diode and take a chance the stator is good or replace the stator. If I have to replace the stator I have to pull the flywheel. To remove the flywheel is a special tool needed or will a regular puller work? I can find no information on what type of diode I would use to replace the broken one.
Engine: Kohler
Model: CV15S
SN: 28094138
Thanks......

[aj-allen]

You are missing the spec # It will start 415?? or 416??

[Skywatcher]

Hi Jim

By your description, it sounds like you have a single wire stator. Remove the remains of the old diode, connect a volt meter set to AC volts between engine and stator wire. Run engine and see what the meter reads, should be well over 16 volts, possibly up to 24 VAC at governed RPM. If you get a good reading, simply solder a replacement diode onto the stator wire and connect back into the harness. A diode like Oregon 33-420 may work, or see what your local electronics repair shop can source for you. Hope this points you in the right direction,

Sky

[Arkie]

Hi Jim

By your description, it sounds like you have a single wire stator. Remove the remains of the old diode, connect a volt meter set to AC volts between engine and stator wire. Run engine and see what the meter reads, should be well over 16 volts, possibly up to 24 VAC at governed RPM. If you get a good reading, simply solder a replacement diode onto the stator wire and connect back into the harness. A diode like Oregon 33-420 may work, or see what your local electronics repair shop can source for you. Hope this points you in the right direction,

Sky

Right: Check for stator AC output before wasting time replacing the diode. You may not need a stator winding if you get little bit lucky.
AND make sure you get the replacement diode polarity in the right direction. (If connected backwards the new diode may turn to dust when your battery or wire is connected and the stator will smoke. A 20 amp diode should be sufficient.
You might use a 10 amp inline fuse in the diode output wire for your first test after the diode is installed for additional circuit protection when you first connect the bat and start the machine.
AND the CV15S engine may be have two wires coming out of the high dollar stator winding from under the flywheel. (one of the wires may or may not be grounded) when you locate the two wires set your VOM or DMM on AC volts and connect across the two wires and check for AC volts per above. (or do a ohms test across the two wires with a ohmmeter, probably less than 10 ohms for a good reading.
Bad reading would be no reading at all on the ohmmeter or very low AC readings of less than 10 volts at high engine rpms'.

Stator price is $50 or more plus labor or installing
Diode is less than $5 and easy to install. (solder into place and use heat shrink tubing over the diode for insulation or a insulation sleeve)

[KE4AVB]

Stator output voltage @3400 is to be 35 vac or higher.

With the present of the diode it tells me you have a 3 amp 70 watt stator with a possible stator brake. The higher output stators usually have an external rectifier/regulator setup.

Stator tests with engine off.

1. Disconnect green stator brake wire if present.
2. With one lead grounded to the crankcase measure the resistance of the black lead. It should be between 0.2 and 0.4 ohms. If 0 it is shorted to ground or if infinity it is open circuit.
3. If green wire present test it as above you get a resistance reading of about 0.7 ohms.

Diode rating should be at least 4 amp avg with a 70 amp surge rating. It also should have a PIV rating of 200 volts. It also should be a ceramic cased version instead of plastic version due the heating involved. Personally I would not solder it in place either for the same heat concerns, instead crimp in place. Anode to stator and the Cathode toward the battery.

Arkie I am actually paying 1.05 piece for the diodes; of course, shipping charges are involved but that is minimal due to that I order them on stock order of my connectors and housings.