DDuplechin 0 #1 Posted January 14, 2015 (edited) Hi All, The battery(new) is not charging on my 2004 71227 16-38HXL Briggs engine. My dad suggested it may be the starter(he was thinking it was a starter/alternator in one unit). I put in a new starter and the gear on the starter only engages the flywheel to start the engine and releases once the engine has started so I'm guessing there is another part that is responsible for maintaining the battery. How does the charging system work on this engine? Is there another part I can check/change? Any help is appreciated! Thanks, Derek Edited January 14, 2015 by DDuplechin Share this post Link to post Share on other sites
rmaynard 14,907 #2 Posted January 14, 2015 Your engine should have an alternator. I don't know for sure, but I think it is under the flywheel. From the alternator, a wire with a diode goes to the battery to keep it charged. Here is a wiring diagram for the charge circuit. Share this post Link to post Share on other sites
DDuplechin 0 #3 Posted January 14, 2015 (edited) could this black and red wire coming from under the flywheel be part of the wiring to charge the battery? The black and red wires connect to the one of the harnesses you see in the pic, they connect to a orange wire and a blue-purple wire. I tried following the purple/orange wires and think they may come to this set of fuses, all fuses are good. I also see there is a terminal block with a large red cover and a heavy guage wire that leads back towards the battery. at the top of the pic is another connection that has the purple wire leadng to it. Edited January 14, 2015 by DDuplechin Share this post Link to post Share on other sites
rmaynard 14,907 #4 Posted January 14, 2015 Here is the complete wiring diagram. I don't see any orange or blue/purple, but that doesn't mean that they aren't there. There appears to be a magneto control wire, a wire for the lights, and an alternator wire coming from under the flywheel. As you can see, red wire seems to be the charge circuit wire. Click to enlarge Share this post Link to post Share on other sites
DDuplechin 0 #5 Posted January 14, 2015 updated my post above with some aditional pics. I have looked high and low and only see the one red and one black wire coming from underneath the flywheel(as described above) Share this post Link to post Share on other sites
rmaynard 14,907 #6 Posted January 14, 2015 Does your 16-38 have headlights? Share this post Link to post Share on other sites
DDuplechin 0 #7 Posted January 14, 2015 yes it does. after looking online for the alternator I think I have found it to be part number 646459 and has 2 wires black and red coming from it to a small harness like in my first pic. It appears it sits in the underside of the flywheel somehow. If I took the flywheel off and visually inspected it are there tell tale signs of it being bad? Looks like its about a $50 part new online Share this post Link to post Share on other sites
rmaynard 14,907 #8 Posted January 14, 2015 Don't take this as gospel, but I'm thinking that the red wire goes from the alternator to the battery with a diode in the line that is converting the AC voltage to DC. The black wire could be from a section of the alternator that is powering the lights. If you go to the manuals section of the forum, you can put in your ID number or search for 16-38's and pull up all the manuals available for your mower. There is probably a service manual and a troubleshooting section may be available. I don't know that there are many members on here with 16-38HXL's since they are not popular with collectors. But if anyone has any experience with one, maybe they will step up and be able to offer more help than me. If the mower runs, and you have a meter, try testing the voltage at the battery when running. A good charging voltage needs to be 13.5 to 14.5 volts DC. Share this post Link to post Share on other sites
DDuplechin 0 #9 Posted January 14, 2015 (edited) ok thanks for the insight I'll look into the manuals, I do have a meter although I have no clue how to use it. She does run, poor thing was put to the stret by my brother in laws neighbor, he rescued it and passed it along to me. I've since changed the following: belt, oil, oil filter, spark plug, fuel filter, starter, and adjusted pedal and rods for better reverse on the hydro..hoping I can get 5-7 years out of it Here's a pic of the part, looks like there is a diode on the red line before the harness Edited January 14, 2015 by DDuplechin Share this post Link to post Share on other sites
rmaynard 14,907 #10 Posted January 14, 2015 You mentioned a new battery in the first post. How do you get it to start if the battery won't charge? Are you charging the battery with an external charger? Will it take a charge and hold it when externally charging it? How old is the "new" battery. Check all your battery cables, especially where the negative wire connects to ground. I have to leave the computer for awhile, but will check your reply when I return later. Share this post Link to post Share on other sites
DDuplechin 0 #11 Posted January 14, 2015 The battery was bought "new" in September. It worked fine after putting in the new battery but after a couple weeks it wasn't starting the engine was weak. It sat up a couple months and now I'm prepping it for spring. This week I bought an external charger and it took the charge fine and in 4 hours it was fully charged and the mower fired up fine with the battery this morning. I'll check connections and report later. Thanks Bob! Share this post Link to post Share on other sites
Howie 882 #12 Posted January 15, 2015 That is a dual circuit alternator. Red wire is the Dc side to charge battery has the diode in it, the black wire is Ac for the lights on the mower. It is unregulated and puts out 2 to 4 amps. Briggs manual does not list how much the voltage should be only that it should put out the 2 to 4 amps at 3600 RPM. Test output with meter going from red wire to positive terminal on battery. Red lead on meter to pin on red wire and black to positive battery. Use 10 amp setting on meter. I don't know if I have one here with that alternator to check voltage or not. With tis alternator lights should not be wired so battery is used for the lights. David Share this post Link to post Share on other sites
Save Old Iron 1,563 #13 Posted January 15, 2015 Briggs manual does not list how much the voltage should be only that it should put out the 2 to 4 amps at 3600 RPM. Test output with meter going from red wire to positive terminalon battery. David The assumption made by the manual is 13 - 15 volts should be available to charge the battery and 12 - 14 volts AC should be available to run the lighting. 1 Share this post Link to post Share on other sites
Save Old Iron 1,563 #14 Posted January 15, 2015 The battery was bought "new" in September. It worked fine after putting in the new battery but after a couple weeks it wasn't starting the engine was weak. It sat up a couple months and now I'm prepping it for spring. This week I bought an external charger and it took the charge fine and in 4 hours it was fully charged and the mower fired up fine with the battery this morning. I'll check connections and report later. Thanks Bob! If the battery sat in a discharged state for months, I would suggest having it load tested. Lead plates in the uncharged battery develop a covering of sulfur crystals which harden over time. Recharging a sulfated battery appears to take a charge but fails in a load test. Leaving a lead acid battery sitting discharged for months is a sure way to drastically reduce its capacity. 1 Share this post Link to post Share on other sites
oaktown1987 82 #15 Posted January 15, 2015 Well a battery doesn't charge an engine Sent from my iPhone using Tapatalk Share this post Link to post Share on other sites
oaktown1987 82 #16 Posted January 15, 2015 Disregard my comment Sent from my iPhone using Tapatalk Share this post Link to post Share on other sites
DDuplechin 0 #17 Posted January 15, 2015 (edited) ok just tested it using the 10 amp setting on the meter(black ground wire on meter to pos pole on battery, red meter wire to red wire pin in harness) reading about 3. So does this mean the alternator is working properly and should be charging the battery? Next step in trouble shooting? Edited January 15, 2015 by DDuplechin Share this post Link to post Share on other sites
Save Old Iron 1,563 #18 Posted January 16, 2015 Looks like you have about 3 amps of charge current flowing to the battery. The stator (alternator) seems to be putting out appropriate charge current. The next test will be to measure DC VOLTAGE across the battery terminals while the engine is near full throttle. You should see 13.5 to 15ish volts to be able to charge a lead acid battery. Voltage higher than 16 would indicate a damaged (sulfated) battery. If you do see near 16 volts on the battery, and the battery case has pop top caps for adding water to the cells, try adding distilled water to top off the cells and recharge the battery. The same voltage test across the headlights terminals with the meter on AC VOLTS should confirm proper stator output for the lighting circuit. 1 Share this post Link to post Share on other sites
Save Old Iron 1,563 #19 Posted January 16, 2015 use this link to test for a properly functioning diode in the DC circuit 1 Share this post Link to post Share on other sites
DDuplechin 0 #20 Posted January 16, 2015 ok just tested the DC Voltage across the battery terminals while running and I am getting 12.31, battery reads 12.35 when not running. I also tested the lighting harness on the ACV 750 and 200 setting and got 0.00 on both, tried swapping the meter leads and got the same reading. Lights DO NOT work How do you go about testing the diode? I looked at your link, is the diode under the small black shrink wrap on near the harness clip in this pic? Share this post Link to post Share on other sites
Save Old Iron 1,563 #21 Posted January 17, 2015 (edited) Usually, on a dual stator setup, one end of each stator winding is connected to ground. Instead of measuring across the diode, you should be able to make a diode check by measuring the diode and the stator winding together. The additional resistance of the stator windings would be irrelevant to the results. Connect one meter lead to the diode terminal in the white connector, the other lead to engine ground (or battery ground). Log the ohms reading. Now reverse the meter leads. The ohm meter should read low ohms with leads connected one way and high ohms when the leads of the meter are reversed. The downside to this method is a high reading in both directions could be either a bad diode, bad wiring or an open stator winding. A low reading in both directions is a shorted diode. A 10x or more change in ohms with meter leads swapped would indicate a good diode. The only way to test the diode directly is to remove some of the heat shrink tubing on the diode lead opposite the connector side. Edited January 17, 2015 by Save Old Iron 1 Share this post Link to post Share on other sites
RubyCon1 62 #22 Posted January 18, 2015 Squirrel CAD LMAO! Share this post Link to post Share on other sites
JustinW.73 224 #23 Posted February 16, 2015 Looks like you have about 3 amps of charge current flowing to the battery. The stator (alternator) seems to be putting out appropriate charge current. The next test will be to measure DC VOLTAGE across the battery terminals while the engine is near full throttle. You should see 13.5 to 15ish volts to be able to charge a lead acid battery. Voltage higher than 16 would indicate a damaged (sulfated) battery. If you do see near 16 volts on the battery, and the battery case has pop top caps for adding water to the cells, try adding distilled water to top off the cells and recharge the battery. The same voltage test across the headlights terminals with the meter on AC VOLTS should confirm proper stator output for the lighting circuit. 15 volts is too high. 13.5-14.8 MAX. Share this post Link to post Share on other sites