Small Engines (Lawn Mowers, etc.): Briggs engine 284707, voltage readings, analog meter

Question
Hi, never used this service before, thanks for donating your time.

I have a Briggs 12hp #284707-1026E1 model engine in my rider. When running, i measure around 18 volts across the battery terminals at full throttle, 12.5 at idle. This is an unregulated charging system. I confirmed the voltage readings at the battery terminals with both a digital and analog meter. Why is it so high? What, if anything, besides the diode in the charging wire restricts voltage to the battery positive side? Does this mean the alternator is shot?

Thank you for any consideration of my questions, sorry it was a long explanation.

Eric

Answer
Eric
how long did it run ? are you having trouble with it charging ?
in order to get a proper reading on a unregulated system you have to hook in a thing called a shunt  What shape is the battery in,is a old one? That may have something to do with it
18 volts is normal after a start it would take about thirty minutes to get to normal,do you have 1 black wire with a white connector on it as this is a 14 v ac unregulated alt. Also the trim numbers you wrote down 1026 E1 do not come up on that type of engine, recheck the numbers.