Simplicity Legacy XL alternator

[R Love]

Hi,
My Simplicity Legacy XL B&S 27 HP diesel will not keep the battery charged. I have replaced the battery and alternator, but still will not stayed charged. I been living with keeping it on a trickle charger between uses. I replaced the alteranator with the same model number, but I would appear to not switch on. So I'm not sure the alernator is the correct one for this tractor.

Does any one have specs/model number for the alternator?

Thanks,
Robert

 

[tomplum]

Have you done basic troubleshooting to know if alternator has output or maybe there is a draw on the system when not in use? I can't say I'm your point guy on this, but more detailed info including actual model numbers and other test info you have could help.

 

[R Love]

Have you done basic troubleshooting to know if alternator has output or maybe there is a draw on the system when not in use? I can't say I'm your point guy on this, but more detailed info including actual model numbers and other test info you have could help.

The tractor is MFG number 1694413
Alternator is a Denso 27060-87212
I tested for the output voltage and am getting About 10V. Should be closer to 14V.

Per the supplier, the Alternator needs to be spinning at 600 rpm or more and have a minimum of 9 volts going to excitation field. All of these require are met.

The alternator was replaced with same model number with the same results. I can be using the tractor at full throttle and the battery charge light stays on when the voltage drops. That's my queue to not stop the tractor unless I can hook up the charger, as it most likely will not have enough power to restart the tractor.

Thanks for your help

 

[tomplum]

A quick breeze in the service manual shows that the two small terminals one of which goes to the charge light and the other to the ignition switch. I would think with a fully charged battery, you should see very little voltage drop to the alternator. I would approach it from that point of view. This could be as easy as a funky terminal. Below is from the Briggs service manual. Further test from the manual calls for a DC shunt, though you can test with a clamp meter too. I found a tractor schematic as well if you can't pull one up online.

The 40 amp charging system consists of a belt driven,
internally regulated alternator, Fig. 19.
The alternator contains a charge light circuit (ìLî
terminal). With the keyswitch in the ON position and
the engine not running the charge indicator light should
light. With the engine running the light should go out,
indicating that the battery is being charged.
If the charge indicator light does not light when the
keyswitch is in the ON position (engine not running),
check the bulb and wiring.
Note: A loose V-belt will cause low DC output.
Belt deflection limit is 9.5-11.5 mm/10 kg
(3/8-7/16 in./22 lbs.).

 

[R Love]

A quick breeze in the service manual shows that the two small terminals one of which goes to the charge light and the other to the ignition switch. I would think with a fully charged battery, you should see very little voltage drop to the alternator. I would approach it from that point of view. This could be as easy as a funky terminal. Below is from the Briggs service manual. Further test from the manual calls for a DC shunt, though you can test with a clamp meter too. I found a tractor schematic as well if you can't pull one up online.

The 40 amp charging system consists of a belt driven,
internally regulated alternator, Fig. 19.
The alternator contains a charge light circuit (?
terminal). With the keyswitch in the ON position and
the engine not running the charge indicator light should
light. With the engine running the light should go out,
indicating that the battery is being charged.
If the charge indicator light does not light when the
keyswitch is in the ON position (engine not running),
check the bulb and wiring.
Note: A loose V-belt will cause low DC output.
Belt deflection limit is 9.5-11.5 mm/10 kg
(3/8-7/16 in./22 lbs.).

I have a connection to the "L" terminal and the battery light does come on when the ignition is first turn on. The light is off when I'm using the tractor. But after a couple days of use, the battery is too weak to start the tractor.

I also have an "IG" terminal next the "L" terminal, nut nothing is connected to it. Should there be?

 

[tomplum]

It looks as though that there are 4 wires on the switch and the M listed in the diagram could very well be what is labeled as IG. So where are you getting your 10 Have you serviced the battery terminals and inspected the harness to that point? I would also perform a draw test . These would give a good baseline of where to go next. I didn't see bulletins on this, but then again am not a Simplicity dealer.

View attachment Simpl_{13899698-022F-4236-B419-316646689448}.pdf