Parasitic Draw/charging questions

[louky]

I'm glad to find this forum as there seem to be many questions answered about the small Briggs engines. I am trying to track down a charging/discharging issue on Sears lawn tractor. Sears 917.256810; Briggs 28N707. I mowed with this for 2 years with no problems. It failed to start a few weeks ago, I put a new battery in it but it obviously didn't cure the problem. It starts fine with a boost from my portable battery pack, but often won't restart even after an hour of mowing. I could use some help in testing to track this problem down. I do have a multi-meter. There are 2 wires coming from under the shroud, red and black, and the red has a diode in it. I have the headlights unplugged and don't really need them.

Should I be getting about 13.6 volts at the battery when running?

What should I read at the battery when I have it on a charger, and what would be a good reading on the battery after charging, I had it on for 24 hours and it is reading 12.3?

What would be a reasonable reading a week later, assuming the battery has both terminals disconnected?

How do I test output of the alternator at the black/red wires? AC or DC? one test lead to the plug and one to the frame?

If I suspect a parasitic draw and want to stop a discharge, is it good enough to just take one lead off of the battery or should it be both?

Does this system have an actual voltage regulator, I can't seem to see one?

Thanks in advance!!

 

[Rivets]

I suspect your stator is bad. This manual will have the procedure to test the charging system.
https://doc-0o-5o-docs.googleuserco...253/*/0B6NaqjIxWV1ySkZjTTA5TGltZEE?e=download

 

[louky]

Rivets: Thanks for the prompt response. I got an error when trying to access your link.

 

[Rivets]

Try this one.

http://www.briggsandstratton.com/~/...gsAndStratton/PDFs/alternator_replacement.pdf

 

[louky]

I got that one. This is pure gold, thanks. I got the battery charged up again, hooked the battery cables back up but unplugged the plug from the stator. I will monitor this for a week and see if the battery stays up.

 

[sgkent]

we had the same happen in our Mercury Sable wagon recently. I spent a month chasing the drain only to find that the new quality battery had a intermittently bad cell in it from the factory. With the cables off that cell drained overnight. A battery will lose very little voltage in a week. Our new battery that works well in the Sable reads 12.45 V when charged. That said, this meter is calibrated and it is not uncommon for meters to be off a fraction. You leaving the plug off test should be a good test too.