Troubleshooting 1811 charging issue

[jmack]

My 1811 isn't charging the battery properly.

The biggest problem I have right now is identifying the exact location of the:

1) rectifier
2) voltage regulator

At full throttle the battery is showing approx ~12V, but as the engine warms up this appears to go down. If I turn on the lights, the voltage drops to ~5v so something is definitely not working.

The service manuals that I looked at weren't very specific in this regard. Images on Google for a Magnum 18 rectifier show a thin metal plate with three leads, but I can't see that on my machine unless it's buried under the shrouds somewhere.

On the left side of the chassis there is a metal box with a 3 prong connector attached to it, but I am not sure if that is the rectifier?

Looking for any one who has gone down this road before for some insight.

Thanks,
John

[j4c11]

Originally Posted by jmack

My 1811 isn't charging the battery properly.

The biggest problem I have right now is identifying the exact location of the:

1) rectifier
2) voltage regulator

At full throttle the battery is showing approx ~12V, but as the engine warms up this appears to go down. If I turn on the lights, the voltage drops to ~5v so something is definitely not working.

The service manuals that I looked at weren't very specific in this regard. Images on Google for a Magnum 18 rectifier show a thin metal plate with three leads, but I can't see that on my machine unless it's buried under the shrouds somewhere.

On the left side of the chassis there is a metal box with a 3 prong connector attached to it, but I am not sure if that is the rectifier?

Looking for any one who has gone down this road before for some insight.

Thanks,
John

It's bolted to the rear shroud and somewhat hidden underneath the intake manifold. You can get to it more easily by taking the intake manifold off.

[jmack]

A picture is worth a thousand words...

Thanks! Going to do this now.

[ol'George]

you prolly can get to the leads without too much trouble, once you locate them as pictured.

Should have about 28 Volts AC measured between the 2 outside leads.
And center lead to ground about 14.5Volts DC @ full throttle.

[j4c11]

Originally Posted by ol'George

you prolly can get to the leads without too much trouble, once you locate them as pictured.

Should have about 28 Volts AC measured between the 2 outside leads.
And center lead to ground about 14.5Volts DC @ full throttle.

To measure the AC you can just unplug the connector and measure directly on the connector. To measure the DC you will have to plug it back in and measure elsewhere, either at the ignition switch or trace the wire corresponding to the middle lead to the next connector. I don't think you can get directly to leads on the regulator due to connector and lack of space between it and the manifold which runs right over it.

[R Bedell]

And center lead to ground about 14.5Volts DC @ full throttle.

That is 14.5 VDC measured from the center terminal to the negative battery terminal.

[ol'George]

Originally Posted by j4c11

To measure the AC you can just unplug the connector and measure directly on the connector. To measure the DC you will have to plug it back in and measure elsewhere, either at the ignition switch or trace the wire corresponding to the middle lead to the next connector. I don't think you can get directly to leads on the regulator due to connector and lack of space between it and the manifold which runs right over it.

I can't speak for a 1811, because I don't have one readily available, but I do have an M-18 in my 782 and although not wide open, the leads can be accessed just behind the air cleaner ahead of the manifold and it does help if the air cleaner is removed.
but maybe there are obstructions on an 1811 that I'm not aware of.
to remove the regulator/rectifier looks a little more entailed as the retaining screws are directly under the manifold runner.
A box/open end and magnet will be beneficial for sure

[jmack]

Follow up on this issue. Thanks for all the responses.

1. Part of my problem was that the dirt on the engine, etc, was making the rectifier very hard to see for someone not familiar with the setup. Once I located it, much easier to figure out! It's not in what I could call a 'serviceable' location on the 1811 or tractors with this engine.

2. I had to remove the intake manifold for proper access/removal of the rectifier. On this particular unit, the terminals were hidden completely when the harness plug is in place, making testing near impossible in the manner described above.

3. Once unbolted, and the connector removed, I could see that the centre terminal was badly corroded and the plug's center receiver was a bit melted. Not good! Further on down the wire, one of the press fit splice connectors was melted as well so that got replaced.

4. I cleaned up the terminals and put everything back together. Once running, the rectifier was putting out ~44VAC from the outer terminals - I am not sure if I was reading or taking it wrong, but that's what it was.

5. The battery was now getting the proper charge and I've been using the tractor for the last couple days without issue.

[R Bedell]

could see that the center terminal was badly corroded and the plug's center receiver was a bit melted. Not good! Further on down the wire, one of the press fit splice connectors was melted

That will do it. It is always good to have good wire, connectors and terminals.

[jmack]

Here's the beast! Having it not working for a while was pretty painful, I had to borrow my neighbors JD 165 (great mower actually) and my Dad's Craftsman, which was pretty terrible, only thing it was good at was sipping gas.

Things are good just needs a bit of a carb tune up...