Yanmar Alternator Not Charging

[sqweeky]

Yesterday I posted this and was not very clear. This is a 3 wire alternator and has an external regulator, I do have a fluke multi meter when checking voltage at the large battery post on the alternator while running I get o volts. Now I know I should have battery voltage at this post but the voltage regulator must not be letting it through. Most videos deal with internal regulator alternators, now I am trying to determine is my problem the alternator,regulator, or wiring at the switch. This tractor is new to me and I suspect wires have been messed with. Thanks

 

[sqweeky]

Also the other 2 terminals are identified by an F and an N.

 

[Harry in Ky]

So you have 0 volts at the alternator output post while engine is running. What does it read with engine off? In MOST cases, that terminal is directly connected to battery positive one way or another at all times. Doesn't matter if key switch is on or off, engine running or not. The voltage regulator has no bearing on that. If you have 0 volts, then you should start by investigating why that is the case.

 

[Janicholson]

All alternators I have worked on have a fuse or fuse link between the output stud and the battery. The diagram I attach is as close as I can get (assuming it is a Hitachi)
The post should have 12v positive. The other wires are as shown (assuming) Jim

 

[Jim in NC]

Rule out a loose alternator drive belt too.

 

[hearnc843]

With 0 volts, that does sound like a bad regulator. I would start there since they are usually fairly cheap, and simple to replace.