Toro 266-H won't Charge

[Iplayfarmer]

Have you checked the fuse yet. If it is a permanent magnet alternator, it does not need an exciting voltage from the battery. If the alternator is good and the engine is running, there should be voltage. If it has an external regulator, there will be 3 or 4 wires from the alternator to the regulator. If the regulator is built in, the voltage is rectified and regulated and sent out to the battery through a fuse.

This regulator has three wires. Two come from the alternator and put out 28 to 50 Volts AC depending on engine rpm. The other is the regulated DC voltage to charge the battery. I'm getting the AC voltage, so I assume the alternator is made with permanent magnets on the flywheel. The book, however, says that the "regulator...must be connected to the battery to function". See below for the evidence of this.

I haven't checked the fuse yet. There are actually two fuses according to the schematic... One between the regulator and switch and one between the switch and the battery. I'll have to check them next time I get some daylight. The main fuse is working because I get power to everything. I'll check that other one.

I hooked up some jumper wires, though, and I'm sure the regulator is working...

Engine off:
B terminal of regulator to Ground = No voltage
B terminal to battery positive = 12 volts (short to ground)

Engine on:
B terminal to ground = no voltage
Battery positive to ground = 12 volts
Battery positive jumpered to B terminal to ground = 14 volts. (regulator putting out charge voltage.)

Now I just have to chase the short. I still can't figure out how to get the cowl off the engine to chase the wires. Back to the books I suppose.

 

[J_J]

That alternator might not be a permanent magnet alternator for this reason. If it is a regular alternator, it need an exciting voltage to start charging. Once it is up to speed, the regulator begins to regulate the current through the field windings. Usually when you turn the ignition on, it send 12 volts to the alternator as an excitation voltage to get things going. Since you put 12 v to the B terminal, you gave the alternator an excitation to charge at 14.2v DC. There might be a broken or disconnected wire running from the ignition switch back to the regulator. If your alternator is putting out 13v to 14.2v, that means that the alternator and maybe the regulator is good.

I believe tere is a way to get max charge from the alternator, and that is to jump 12v DC to one side of the field .

Alternator Terminal ID's



'S' terminal
Senses battery voltage

'IG' terminal
Ignition switch signal turns regulator ON

'L' terminal
Grounds warning lamp

'B' terminal
Alternator output terminal

'F' terminal
Regulator Full-Field bypass

 

[J_J]

I found a nice signal tracer at Home Depot that does a good job at tracing wires on automobiles, and tractors. First disconnect the battery, and connect the beeper to the wire you want to trace. Then you take the other part of the unit and follow the beep. When you can not detect a beep anymore, the wire is broke or unplugged. If it stops at a fuse, the fuse is probably bad.

 

[Iplayfarmer]

I've identified the problems. The symptoms were actually caused by two issues.

There was a short to ground in the fuel shut-off solenoid. I'd already pulled the guts out of the solenoid valve earlier due to another problem, so I just disconnected it. Now there's no more voltage between the positive terminal and the regulator B terminal.

The other problem is that there was some kind of short in the fuse block. The fuses were all good, but when I moved the wires going to the fuse block, the battery warning light on the dash would come on and off.

I couldn't see any obvious wear points or breaks in the wire, so I sprayed a bunch of electrical cleaner in the whole fuse block and blew it out with compressed air. I put the fuses back in and it seems to work now. I ran the mower for a few minutes with the lights on, and the battery warning light never came on. Knowing the nature of electrical shorts, though, I won't be surprised if the problem re-appears. This time I'll know what to look at first.

 

[J_J]

I really don't think you had a short. A fuse would blow or the wires might burn and melt. If you don't have a voltage from the ignition switch to the alternator, it will not charge, and the low battery light will come on. Now if you jump a wire from the battery to the ign terminal on the alternator, it might start charging and the low battery lamp will go out.

 

[dqdave1]

sounds more like dirty /loose connections.

 

[Iplayfarmer]

I really don't think you had a short. A fuse would blow or the wires might burn and melt. If you don't have a voltage from the ignition switch to the alternator, it will not charge, and the low battery light will come on. Now if you jump a wire from the battery to the ign terminal on the alternator, it might start charging and the low battery lamp will go out.

I guess "short" is actually the wrong term for it. What I had was a loose connection. The fuse box connections for the wires going between the battery and the regulator were not making the connection all the time; and, therefore, I wasn't getting voltage to the regulator so I wasn't getting charge to the battery.

I did have a short going to that fuel solenoid in that I was getting continuity to ground with it. It wasn't a very strong connection; or, like you said, it would have blown something. I did notice previously that if I let the mower sit for a while without starting it, I'd have a low battery. A slow drain due to a weak short would explain that.