QuestionYes, I do have a DC voltmeter. Another clue - a wire overheated to the point it burnt all the way through. It was leading to an area around the flywheel.
-------------------------
Followup To
Question -
I have a B&S 12.5 twin cylinder engine, model 404437, made in 1988. It runs great, but the battery drains down after about 10 starts. I assume the alternator is not functioning (the battery is brand new). I need help locating where to find the alternator as well as how to test if that is indeed the problem. I am able to jump start the engine just fine.
Answer -
The alternator is under the flywheel. Do you have a DC voltmeter?
Let me know.
Eric
AnswerThere is a diode in the harness near the alternator that fail once in a while. Check the battery voltage with the mower off, then with the mower running at idle, then full throttle. You should see some increase in voltage as you increase engine speed. How many wire(s) run to the alternator?
If you have only one wire, then it is DC. Should be above 12 DC with the engine at high speed. If 2 wires one is AC but that does not charge the battery.
The best method to check the alternator charging is to use a DC shunt, but these are expensive and I rarely use the one I have...the old voltage test works well.
Alternator wires rarely melt except if the battery is connected backwards...don't laugh...I've done this once and fried the alternator diode and wire.
Let me know what you find.
Eric
