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buddy10297

Starter wiring help

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buddy10297
Hello everyone! I have a 728 simplicity broadmoore with a starter generator system. The starter generator is broken and I hae a regular starting system with a starter taken from another tractor which I would like to install. This one has one wire coming from under the flywheel charging system and I would like to know how would I go about converting to the regular starting system from the starter generator system. What do I have to change? and what wire do I have to omit and rearrange? I hope I'm not the only one with this problem....and I hope someone has some insight on this conversion. I've been reading all of the past postings but I haven't come across anything of the sort. Thanks!

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ZippoVarga
Buddy........The reason you have not been able to find anything on switching from a S/G system to a Starter/Alternator system is because Briggs underwent a transformation that was extreme enough that the parts do not interchange easily. You would have to disassemble the entire engine, pull the crank shaft and replace it with a later model crank. Taking into consideration that all the pertinent diameters should be checked to make sure they will match up with the oil pan bearing, top bearing, connecting rod, cam gear, input and out put diameters and lengths along with possible tapered shafts and so on. This is taking into consideration that the original block was not designed to accomodate the added components beneath the flywheel. Then you have the different configuration of the flywheel....with a series of magnets attached to the underside of that, then the space needed to provide clearance for the stator and the lack of mounting holes to attach the stator to the block, which coupled with the magnets gives you your charging capabilitles. In short, it's cheaper to either replace your engine with a later model or go to e-bay and get another Starter/Generator. I strongly suggest if you opt for the latter, that you also have the regulator inspected for any flaws. If a regulator is out of adjustment on these lower amperage starter generators they can easily cause the charging poll of the S/G to burn out that section of the commutator, rendering the generator part of the S/G useless. A regulator for these tractors should never allow more than 14.5 volts to pass through it before switching soley to battery power. The Starter/Generators are plentiful. If your end plates are in good shape. Meaning the bearings are ok. Then you can almost buy ANY S/G and simply replace the end caps to fit your engine. Just be careful when you remove the pulley side of the S/G. The brushes, of which there are four (two charging and two starting), will need retracted. I generally use annealed bailing wire or solid core 18 guage copper wire to secure them back because those types of wire easily pull out once you are sure the brushes are past the end of the commutator. I hope this sheds some light as to why you have not found any topics on a conversion from a S/G to a late model starter and charging system. Most automotive electrical repair specialists can test your S/G and regulator to determine their problem. Your description was pretty vague as to what was wrong with your S/G. A sloppy end cap bearing can wreak havoc on the pole shoes inside the S/G and cause hot spots that will eventually burn out the poles copper windings or the armature's windings. If you are not sure as to the cause of your S/G's failure then I suggest starting fresh with another S/G that is known to be good and just replace the bag S/G. There are more variables that would make your life miserable if you tried converting a S/G unit with the conventional starter and alternator systems of today. But I feel i've covered enough that you get the general idea that it's not an easy task. Nor is it plausable or recommended. Good Luck!!! Sean aka Zippo

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buddy10297
Hey Sean, thanks for all of your help. I do have a later model engine with a starter which I would like to put into the tractor. I need a new wiring diagram to work with this engine. Do you have any ideas? The problem with the starter generator was with the bearing close to the upper pulley, it collapsed and burned the starter generator. thanks again.

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ZippoVarga
Buddy, The newer engines can have as little as two wires or as many as 6 to contend with. The best thing I can suggest is to go to the briggs and stratton web sight and download the PDF parts manual for the engine you are wanting to put in. This will show you the different stator types so that you can accurately determine the amperage of your alternators output. Also, be prepared. Driveshaft location, length, mounting holes, throttle and choke cable locations on engine, fuel line length can and usually are all affected with an engine swap along with the wiring changes. Going from a S/G to a conventional starter system on the later briggs is desired by a lot of people who want a dependable system with out the bulk of the S/G, but if your current engine is ok, I still reccomend replacing the S/G. Only because that's my preference, not for any other reason. Let me know what you find out on your newer engines wiring and we'll all try to help you out. I'm just a half witt compared to many of these guys in here and we're all happy to help out. And welcome to the club by the way!! Sean

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PatRarick
As to putting a starter system on your old engine, remove the flywheel and I believe you will find "towers" cast into the block to attach the stator. You should have an eight horse engine, so if your donor engine was also an eight horse, the parts should bolt right on. I'm reasonably sure the 728 is new enough to have all the provisions on the engine to convert it over. If those towers are cast in the block, you'll be okay. If not, you'll have to either have the S/G repaired, or go with a newer engine. In either case, whether you convert your engine or install a newer engine, we first need to know the color of the wire and the connector that comes from the stator under the flywheel. It may be painted, and if so, remove the paint to find the actual wire and connector color. Does it have an area covered with heat shrink tubing fairly close to the connector? That is the first that we need to know to see if a regulator is needed. Converting the wiring is a very simple matter. You eliminate the two wires from the S/G to the voltage regulator. Connect the wire from the stator under the flywheel to the wire that went on the battery terminal of the voltage regulator. Depending on your stator, it will either be hooked direct, or through a Briggs voltage regulator. The cable that originally went to the starter generator from the starter solenoid or push button starter switch, will connect to the starter of the newer engine. Pat

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buddy10297
Thanks for all of your help so far! I checked the engine and there are two wires under the flywheel (which is attached to the stator) the colors are black and pink with a connector. I'll will work on it tomorrow but I'll check for replies first thing in the morning before I start tinkering. Thanks again for all the valuable information.

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gregc
If that's black and red (instead of pink) with a white connector then you have a dual circuit alternator (14 volts AC minimum @ 3600 rpm, 2-4 amp DC unregulated). The black wire is the AC output and the red wire is the DC output. The raised rib on the connector indicates the DC side. http://www.briggsandstratton.com/miscpdfs/RNT/alternator_id.pdf http://www.briggsandstratton.com/miscpdfs/RNT/alternator_replacement.pdf http://www.briggsandstratton.com/miscpdfs/RNT/ignition_wiring.pdf

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