Hendricksn 10 #1 Posted July 12, 2013 Hi all I have a 416-8 that has the onan p216 engine in it and its not charging. I ran a volt meter and there's no change in voltage coming out when I change rpms. Is there an alternator on it because I looked at the starter and there's an extra cylinder on top. Or is it like the older onans that have the magnets underneath the flywheel? Thanks in advance Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,392 #2 Posted July 12, 2013 Simple things first. This is done with the engine NOT running. Check voltage across the battery posts and record it. Now move the red test lead to the DC+ terminal on the voltage regulator. You should have the same reading. If not follow that lead back towards the battery until you find the fault. Let us know what you find. Stator is behind the flywheel. Garry Share this post Link to post Share on other sites
Hendricksn 10 #3 Posted July 12, 2013 I found a page about how to test that and I got 12.3 at the battery and 12.3 at the voltage regulator. There was no ac voltage coming out of either of the two posts next to it I found a page about how to test that and I got 12.3 at the battery and 12.3 at the voltage regulator. There was no ac voltage coming out of either of the two posts next to it Share this post Link to post Share on other sites
Jeff-C175 7,206 #4 Posted July 12, 2013 You set the meter to read AC Volts? And with one meter probe on one of the AC terminals and the other on the other, you had ZERO? Disconnect the AC from the regulator and measure again with engine running. Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,392 #5 Posted July 12, 2013 The wiring sounds to be OK between the regulator and the battery. To test the AC remove the wire connector from the regulator and place the test leads on the AC wires. One lead on each wire - doesn't matter which one is where. Now start the engine and see what AC voltage you get. Don't forget to change your meter to AC. Garry Link to Onan service manual Share this post Link to post Share on other sites
Hendricksn 10 #6 Posted July 13, 2013 I got 21 volts ac. Is that good or bad Share this post Link to post Share on other sites
Jeff-C175 7,206 #7 Posted July 13, 2013 21 VAC might be OK if the engine is idling. What is it when engine is at speed? Share this post Link to post Share on other sites
Hendricksn 10 #8 Posted July 13, 2013 Oh I only checked it at idol. I'll check it again tomorrow Share this post Link to post Share on other sites
Hendricksn 10 #9 Posted July 13, 2013 21 at idle 42 at mid throttle and 55 at full throttle Share this post Link to post Share on other sites
Jeff-C175 7,206 #10 Posted July 13, 2013 I think that sounds fine. 55VAC even sounds high... but I'm not familiar with Onan, so it could (probably is) OK. Kohler twins are about 38 VAC at full speed. Point is though that you have enough, if not more than enough to charge the battery if the rectifier/regulator is working. If the DC output of the regulator never goes above the battery voltage, then it seems pretty clear that the rectifier/regulator has taken a dump. You should be seeing around, or a little more than, 14VDC when the engine is running at speed, but not more than say 14.5 -ish (with a KNOWN GOOD battery installed!) If the battery is 'soft' is it possible for the voltage to go higher. Share this post Link to post Share on other sites
