Ed Fox 20 #1 Posted July 30, 2019 (edited) Hello, I'm back to trouble shooting my battery and over voltage issue. It's a 312-8 and after it warms up the voltage pushes into the 18-19 volt range. I searched on here and a few threads mentioning there should be a resistor to cut down the voltage. I checked the grounds, looked for the resistor and no luck finding one anywhere. I started to look closer at the parts manual and in the engine/charging section they do show a regulator. Is it possible that it would me mounted under the flywheel? I can not find this thing anywhere Edited July 30, 2019 by Ed Fox Share this post Link to post Share on other sites
Ed Fox 20 #2 Posted July 30, 2019 Hello, I'm back to trouble shooting my battery and over voltage issue. It's a 312-8 and after it warms up the voltage pushes into the 18-19 volt range. I searched on here and a few threads mentioning there should be a resistor to cut down the voltage. I checked the grounds, looked for the resistor and no luck finding one anywhere. I started to look closer at the parts manual and in the engine/charging section they do show a regulator. Is it possible that it would me mounted under the flywheel? I can not find this thing anywhere Share this post Link to post Share on other sites
Ed Fox 20 #3 Posted July 30, 2019 Sorry for the 3 posts. Was trying to add the picture and not sure what I did. If a moderator could please remove the other two posts. I dont see the option . thank you! 1 Share this post Link to post Share on other sites
new2horses 287 #4 Posted July 30, 2019 Ed, I've never seen a resistor in any of the Kohler charging systems. I can tell you that alternator voltage should be 28-32 VAC with voltage out of the regulator at half that but DC. Voltage regulators are pretty easy to find and relatively inexpensive to purchase. Best wishes, David 1 Share this post Link to post Share on other sites
953 nut 56,432 #5 Posted July 30, 2019 Your voltage regulator is mounted to the upper part of your flywheel fan cover. It has a three wire flat connector with all of the wires going behind the fan cover. If the regulator/rectifier is not properly grounded the voltage can go higher than normal. Remove the two screws that hold it in place and clean the contact area with a little steel wool or sandpaper. 3 Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,161 #6 Posted July 30, 2019 The voltage regulator if used is mounted in the blower housing so the back of it is cooled by the air from the flywheel fan. They have 3 wires going to it. If you have a 1985 or 1986 model tractor they did not use a voltage regulator. These use a dual flywheel stator. One stator supplies AC (Alternating current) power for the lights so the lights only work with the engine running and the faster the engine runs the brighter the lights. The 2nd stator also produces AC current but they added a diode to the output lead to rectify the AC current to DC (Direct current) to charge the battery @ 3 amps. The voltage is not regulated. The theory is the stator is small enough that it can not overcharge the battery but as you are finding out it can. Digital voltmeters can pick up stray interference from the engine when it is running giving a false reading. Analog meters react slower and may give a more accurate reading. Compare the dash gauge (Analog) reading to the digital reading with the engine not running. If they are close use the dash gauge reading when running. If the voltage is still high you need to get creative. Some have added diodes in series to the one that is already there. As the charge current passes through each diode the voltage drops about .6 volt. Depending how many are required it is hard to insulate them and protect them from damage. Briggs & Stratton have a small regulator that should work but have never tried them. The simplest way to control the voltage would be to turn on something to use up the extra power like lights or an electric clutch but you have neither. If you added a single-pole double-throw switch to the lights you could run the lights off the battery when the voltage got high. Just thinking with the keyboard here. Garry 1 Share this post Link to post Share on other sites
Ed Fox 20 #7 Posted July 30, 2019 Gary, this sounds exactly like my situation. I'm not the original owner, a good friend if mine was but he told me he bought this in the mid 80s and the lights only work when the machine is running . I'm assuming the factory diode is installed close to the coil as I see nothing inline with the wires that are out in the open. There is a two wire molex type connector that is exposed maybe 10 inches past the engine that comes from under the flywheel and I'd have to assume these are the charging wires. If I were to use a voltage regulator I'm not sure how to connect it. For one there are only two wires and all of the voltage regulators I've looked up have three terminals. Any idea? The help is greatly appreciated Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,161 #8 Posted July 30, 2019 There are 3 wires from behind the flywheel. One is ground wire to kill the ignition. Another is a stator AC lead going to the headlamp circuit. (Tungsten bulbs will work with AC or DC current.) The last is a stator AC lead that has a diode added near the end of the wire/connector. The diode will be about 3/16" diameter x 5/16" long and you should feel it by squeezing the insulation or plastic tubing covering it. B&S info. I'm thinking H 5 amp may work if you have 28 volts AC going into the existing diode. If B&S can use a single charge wire you should be able to also. Another that may shed some light on the subject Garry Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,161 #9 Posted July 30, 2019 A few choices for the 691188 B&S regulator https://www.rcpw.com/search/?quest=691188 Garry Share this post Link to post Share on other sites
The Tuul Crib 7,338 #10 Posted July 30, 2019 1 hour ago, 953 nut said: Your voltage regulator is mounted to the upper part of your flywheel fan cover. It has a three wire flat connector with all of the wires going behind the fan cover. If the regulator/rectifier is not properly grounded the voltage can go higher than normal. Remove the two screws that hold it in place and clean the contact area with a little steel wool or sandpaper. Share this post Link to post Share on other sites
Ed Fox 20 #11 Posted July 30, 2019 1 hour ago, The Tool Crib said: Thank you TC. I didnt ignore the post buddy. I'll check again but I'm pretty sure theres nothing there. The wires come right up from behind the flywheel and connect to a molex connector about 10ish inches from the block. Share this post Link to post Share on other sites
Ed Fox 20 #12 Posted July 30, 2019 The last picture is what I assume are the charging wires. Comes out from behind the flywheel. I thought it was two wire but after looking this morning its three wire in the connector. So i guess i just need to install a regulator on those wires? If so I still dont understand it enough to know what wires will go where on the regulator. Any idea how I can figure that out? Share this post Link to post Share on other sites
The Tuul Crib 7,338 #13 Posted July 30, 2019 There should be 3 wires coming from the stator . Those go to the regulator. Share this post Link to post Share on other sites
Ed Fox 20 #14 Posted July 30, 2019 4 minutes ago, The Tool Crib said: There should be 3 wires coming from the stator . Those go to the regulator. The last picture I posted are the three wires that are coming from behind the flywheel. The are broken buy the plug I'm showing in the last picture. They run to the ignition switch and the analog volt meter. I'm assuming I need to install a regulator inline with those three wires. I just don't know how t connect it...what wire would go where and once I connect the three wires how am I continuing the knocked down voltage to the ignition switch and volt meter? Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,161 #15 Posted July 30, 2019 Find the diode and replace it with the 2-wire B&S regulator. Connect the correct yellow regulator wire to the stator wire and the other red wire to the charge terminal in the 3-wire connector. The aluminum body of the regulator is grounded by the mounting screw when fastened to the chassis. Try to mount it so it is not in the path of engine heat as the aluminum is what disperses the heat it generates. https://ca.images.search.yahoo.com/search/images;_ylt=A2KLfRkaVEBdD4kAphLrFAx.;_ylu=X3oDMTEyOXVnaGpyBGNvbG8DYmYxBHBvcwMxBHZ0aWQDQjY1NzFfMQRzZWMDc2M-?p=691188+regulator&fr=mcafee Garry 1 Share this post Link to post Share on other sites
Ed Fox 20 #16 Posted July 30, 2019 Thank you, I ordered one. 10 bucks didn't hurt too much. I just need to figure out which wire the OEM diode is on. Ill look at the harness closer but I'm pretty sure they installed it behind the flywheel as I didn't see a "bump" of any sort in the harness. Not the end of the world but just more work. Ill update everyone once I have the time at the end of the week to dig into it. Thanks again for all of your help! Ed Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,161 #17 Posted July 30, 2019 The diode should be close to the end near the plastic connector. I don't know if the connector you are working with has the male or female terminals. If female here is what they look like and can be removed for replacement. Install a new terminal on the red wire and plug it back into the connector. You could also extend the yellow and red wires if it would make a neater installation. Just added a picture of the male terminal to the same page as the female. Garry 1 Share this post Link to post Share on other sites
oliver2-44 10,016 #18 Posted July 30, 2019 While you have the large cowling off, I suggest you pull the other engine tins and give your engine a good cleaning. While your's don't look terrible, these air cooled engines rely on good airflow to remove the engine heat. Your picture shows some buildup on the valve area and some fins that would be good to remove. Since your having voltage charging issues, now would be a good time to do some general maintenance on the charging system. I'd be very tempted to pull the flywheel and gently clean the stator coils with a tooth brush. I suspect the coils and magnet are behind the flywheel are completely packed full of grass/dust/grease. The 3 older horses (1974-1985) I've bought had been used for mowing duty and they were beyond packed. 1 Share this post Link to post Share on other sites
Ed Fox 20 #19 Posted July 30, 2019 6 hours ago, gwest_ca said: The diode should be close to the end near the plastic connector. I don't know if the connector you are working with has the male or female terminals. If female here is what they look like and can be removed for replacement. Install a new terminal on the red wire and plug it back into the connector. You could also extend the yellow and red wires if it would make a neater installation. Just added a picture of the male terminal to the same page as the female. Garry Found it Gary, thank you very much. 2 Share this post Link to post Share on other sites
Ed Fox 20 #20 Posted August 4, 2019 Just to let every one know. The B&S regulator worked. Dropped the voltage to 13-14 at full throttle. Thanks again! Ed 3 Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,161 #21 Posted August 4, 2019 Thanks for posting the results. I could not see why it wouldn't work and you proved it does work. Garry 2 Share this post Link to post Share on other sites
Moonkie Man 0 #22 Posted July 8, 2022 Hi all, first time posting but not new to the site. I am planning on doing this since my 310-8 is reading way high also. I just want to be double sure that this regulator replaces the diode or does it go after it on the wire? I thought the regulator couldn't convert AC to DC, only regulate the voltages hence the name. Thanks. Moonkie Man Share this post Link to post Share on other sites
953 nut 56,432 #23 Posted July 9, 2022 You probably should start your own post and include the engine model number, spec number and a photo of the component you plan on installing. Not all 310s have the same charging system. Just click on this link and you can begin your own post. https://www.wheelhorseforum.com/forum/65-wheel-horse-electrical/?do=add Share this post Link to post Share on other sites
Handy Don 12,890 #24 Posted July 11, 2022 On 7/8/2022 at 3:22 PM, Moonkie Man said: Hi all, first time posting but not new to the site. I am planning on doing this since my 310-8 is reading way high also. I just want to be double sure that this regulator replaces the diode or does it go after it on the wire? I thought the regulator couldn't convert AC to DC, only regulate the voltages hence the name. Thanks. Moonkie Man Yep, the term regulator originated with DC only systems but got appropriated (and arguably poorly used) for AC to DC units. Where WH engines with stators have regulators, they all convert AC to DC and regulate the output voltage (some with greater control than others). Where WH engines with starter/generators have regulators, they regulate (i.e. limit) DC current and voltage Where WH engines have only diodes, they are chopping AC into DC "pulses" and the only regulation supplied is the resistance of the diode and battery as well as the engine speed. Share this post Link to post Share on other sites