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Briggs Magneto question


Ketchamized

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I have the 243431 Briggs engine, 10hp cast iron, original engine of AC B-210- I noticed something that seemed out of the ordinary... On my other engine and other engines that I've worked on- has just one black wire going under the points cover going to the mag. But, on the AC B-210 tractor I recently accquired, I noticed that there are two wires coming out from under the cover of the engine- one is a medium thickness black wire that goes to the points. The other one is a thinner black wire that goes to a tab mounted outside the points, via the top screw of the points cover. Why would there be two wires? I'd like to note that my tractor keeps shorting out. Is it because of the two wires?
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One goes to the points the other on the terminal block is connected to the key switch which puts a ground on the coil when turned to the off postion to shut the engine off.
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Maynard, Thank you for your response. :) The 2nd wire goes under the cover along with the mag wire... Seems to go in the same general location where the mag is. In addition, there's a white wire that goes from the key switch to that terminal block you mentioned. Odd. I do wonder if the previous owner added a 2nd wire or extended the ground wire to the terminal block? It looks like I might have to actually remove the shaft and the cover to find out.
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There is an insulated lug screw under the flywheel on most cast iron series engines where the mag. kill/points wires junction. At anytime dureing it's life time someone may have added an extra wire or changed the mag. or any other combination. Normally there is one wire going to the insulated block over the points box and it junctions there to the key switch and the points. But anywhere on any of these wires it can short.
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D-17 Dave, Thanks for the info, that makes a lot of sense now. How is the insulated block supposed to be insulated? On my engine, there's a metal tab that is connected to the top screw of the box. Is there supposed to be a washer seperating the tab from the box? Thanks again,
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quote:
Originally posted by Ketchamized
D-17 Dave, Thanks for the info, that makes a lot of sense now. How is the insulated block supposed to be insulated? On my engine, there's a metal tab that is connected to the top screw of the box. Is there supposed to be a washer seperating the tab from the box? Thanks again,
There's supposed to be an insulator between the points box and that metal tab. One end of the insulator mounts to the top screw of the points box and the metal tab (or male spade connector) mounts on the other end of the insulator. Briggs part number 66895. Briggs retail price is $1.35
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The tab on the points box is an insulator itself. That's why they break so easy. The screw under the flywheel schroud is a bolt with plasic washers between the backing plate abd the screw.
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gregc & D-17 Dave, Thanks guys... I am suspecting that the 2nd wire is rubbing against the back of the flywheel... Causing it to rub off the rubber coating off the wire- and the wire's touching the flywheel as it spins. That would explain the fluctuations in power as shown on the ammeter. It'd also explain why even though the carb is shiny clean, everything in perfect order- and it only starts for a few seconds then shuts down quickly. Best Regards, Erick
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Erick, Don't get the magneto circuit confused with the charging circuit. A short in the ground wire from the magneto will not show up on the ammeter. The magneto is a totally separate circit and is not connected in any way to the ammeter. A short in the magneto wiring will affect engine operation, but will not affect the charging of the generator when the engine is running, other than shutting down the engine.
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Rod, I know for sure the medium thickness wire goes from the points to the hub behind the flywheel, then to the mag. But I'm not sure what the 2nd wire's function is. It follows the mag wire underneath the shroud. It seems that the more I talk with you guys, it looks like I'm going to have to take the shroud off and take a look at the flywheel, mag, and the wiring behind there- there's one wire too many behind there. I dread having to go through all of that trouble just to get behind that shroud. Any idea of what the function of the 2nd wire might be? It just struck me as odd that there would be a 2nd wire when it's not necessary.
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On some of them there are two wires that basically connect to the same place. One goes directly to the points. The other goes to the ignition switch to short out the magneto when the engine is turned off. Leave the one wire hooked to the points and take the other wire loose and leave it hanging so that it doesn't touch anything then see how the engine runs. With the engine running, then touch this extra wire to ground and see if it kills the engine. If this wire kills the engine, then it should be connected to the shutoff wire from the ignition switch. On my 713 I hooked the kill wire directly to the shutoff wire from the ignition switch without using the screw connection.
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quote:
Originally posted by UCD
One goes to the points the other on the terminal block is connected to the key switch which puts a ground on the coil when when turned to the off postion to shut the engine off.
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Rod, Thank you for your response, and for spelling it out for me. :) Very much appreciated. Will give it a try tomorrow and see how that goes. If that turns out to be the problem, it'll save me $$ and a trip to the tractor repair shop. :) From what I've read, it seems to me that the "insulated" tab on the terminal cover is supposed to be made out of a material that is supposed to be insulated. On my tractor, it looks like it's a piece of metal- very conductive. Perhaps it's been starting, shutting down, starting, shutting down, etc. because of that tab. It's on loosely too, so that might have been a factor. Maynard, Thank you for your response. As always, you're a wealth of information! :)
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UPDATE: Rod & Maynard- Thank you guys so much. It solved half of the problem. :) It now runs constantly without quitting for the first time! It roared to life... Fantastic! Kill switch works well too.. But one problem: fuse keeps burning out. Had to force the wires to touch each other until it started to smoke & fuse together in order to keep it running. Here's what I did: Removed the 2nd wire going to the tab on the outside of the points cover- let it dangle and it started up immediately. (I was impressed, actually, at how fast it started.) I touched the wire to the tab, and it shut down. So that tab is definitely not original & is conductive. The previous owner must have thought that it was just a matter of replacing the tab with a metal tab, when in reality, you needed an insulated tab. So, I connected the kill wire to that 2nd wire and put black tape on it. Started the engine, started right up, ran really smoothly even at low idle. But the wires where the fuse was- got really hot and fused together. Since the engine operation is perfect, it has to be the generator generating too much electricity and blowing out the fuse? The wires are all thick, in good condition, and nothing is rusted. Thanks
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"Since the engine operation is perfect, it has to be the generator generating too much electricity and blowing out the fuse? The wires are all thick, in good condition, and nothing is rusted." Eric, The wires shorting indicate a short or load in tghe system, not a an overcharge from the gen. There could be several different problems in the chargeing circut or a combination of problems such as incorectly wired. I'd sugest looking in the manual for the wireing diagram and traceing everything out before running it any more. If they aren't already damaged you could kill the regulator, gen. or melt the wires worse.
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Dave, Thanks. Appreciate that. Wiring matches exactly to the diagram, checked 4 times. Only thing that looks different is that 2nd wire (kill wire from mag)... Diagram doesn't show that 2nd wire. All the electronic compotents were tested and found to be in 100% working order. I'm going to give up on it and bring it in to a garage. Thank you for your help. I tried my best, and a smart man is one that knows when it's time to pack the bags.
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Erick, Just leave the extra wire un-attached till you find out what it is. If the tractor runs good with it disconnected, then don't attach it to anything. Wrap it with tape and let it dangle. Since by connecting it to the other wire, you are getting hot/fuzed wires and blowing fuzed, it is almost for sure that the second wire is connected somehow to the charging system instead of the ignition system. None of my tractors have a fuze in the ignition system. The fuze is always in the charging system. The magneto ignition and the charging system should only have one point on the tractor where any of the wires connect to the same place, and that is the ignition switch. Even in the ignition switch they don't connect together, they are just operated by the same switch. As I said, leave the wire unhooked, tape it off so it won't short out, and check out the operation of the engine and charging system with that wire unhooked. Biggest mistake most people can make is to try and hook up every wire on the tractor before starting it. Done that myself and burned up things before too. On the last couple tractors that I have purchased, I unhooked the charging system if the wires didn't look correct, got the engine starting and running properly. Then I went thru the procedure of checking out the charging system and getting the wiring correct. You never know why a previous owner may have added this extra wire, or if the engine has been swapped from some other machine that used the wire for some reason. I have rewired quite a few machines because the previous owner had a better idea about how to fix a problem. Right now, you have me believing that the extra wire is not needed, and that if you tape it off and don't connect it to anything, the tractor will most likely work fine. If the tractor will not shut off with the wire unhooked, then connect the extra wire to the engine kill wire from the ignition switch. That wire should short to ground when the key is turned off. These normally connect on a terminal block, but on the only tractor that I have with a magneto ignition, I just spliced the wires together without a block, since the block was broken off when I got the engine. Just make sure the wires dont dangle in a way that they can get caught on things or wear away the insulation. Cable ties work nice for holding wires in one place. As I said above, if the tractor works fine with the wire unhooked, then leave it unhooked. If the wiring diagram says it doesn't exist, then the answer may be that it shouldn't be there, so don't hook it to anything until you are absolutely sure what it is for. Just my opinion, use it as you wish.
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I have 3 B series Allis Chalmers 2 HB-212's 1 B-110 and a Simplicity 3212H. They are all wired per the diagram you posted. All of them have 2 wires from the coil/mag one to the points and one to the terminal block that is attached to the outside of the points cover. The white wire from the ignition/start switch is connected to this wire on the terminal block with a small machine bolt. The white wire from the switch to the mag is actually connected to this Bakelite terminal block attached to the top mounting bolt of the points box which is not shown. Also not shown in the wiring diagram is the Briggs side of the ignition circuit i.e. the wire from the coil/mag to the points inside of the points box or the spark plug wire from the coil/mag to the spark plug. There are two separate circuits 1. Starting circuit. 2. Ignition circuit. The Starting circuit is shown in the diagram. The Ignition circuit is not shown. It consists of the wire from the coil/mag to connected to the points inside of the points box and the spark plug wire from the coil/mag to the spark plug. I modified this diagram to show the bakelite terminal block and points box. I did not include the wire from the coil/mag to the points. The terminal block is Briggs part# 66895 cost $1.25 and is available from a Briggs dealer or Simplicity dealer.

According to your description you have TWO problems one problem with the ignition circuit and one with the starting circuit. The fuse is in the starting circuit.

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Rod, That sounds very doable. I will re-check my wiring again using Maynard's colored code diagram and see if I overlooked anything. If things are still the same, then I will do as you suggested as a temporary measure until it's time for me to get it fixed. I really wanted the tractor to be 100% original. :) It's still a great solution so that I can use the tractor in the meantime. Sincerely, thank you for that tip. :) Maynard, Thank you for the color coded diagram. It will help me re-verify the wiring. While engines and mechanical items are my areas of strength, I am usually at a loss when it comes to the electrical system. It's something I'd like to learn and do the right way. It makes me nervous working on the electrical system on this particular tractor, since the electrical system is entirely brand new, and the previous owner really spent a lot of money on the electrical compotents, wiring, and etc. I can tell you for sure that my terminal tab on my tractor isn't original, nor is it made out of bakelite. It's a piece of steel... Doesn't look original. Looks like it was sawed off of a longer piece of steel. Once I removed that, the engine ran constantly for the first time. So, that's one problem off the list. :) Also, thank you for taking the time to help, I really appreciate that... That goes for the rest of you guys too. It really does help keep me motivated and not wanting to fail you guys. (As well as fail myself) :) UPDATE ON EDIT: Maynard, I used your diagram and looked closely, and just noticed that according to the diagram, the positive and negative wires on the solenoid was reversed. It was confusing, because the placement of the generator and the battery wasn't "location-proper" on the diagram. Had to turn the paper around a few times, and trace the wiring. It threw me off, the fact that my other tractor, the wiring was wired the same way. (reversed) This probably is due to the fact that there's an automobile coil retro-fitted to the other tractor. So I couldn't depend on that one as a basis for comparsion. Once I reversed the wires, sure enough... It stopped getting hot. So I knew, that right there was the solution. I turned it on, let it run for a couple of minutes... Ran great. Nothing was hot or smoking. Turned it off. Tried again. Same thing. The 3rd time, the fuse blew. Figured that maybe I tried to start it too many times. So, I went ahead and touched the 2 wires, bypassing the fuse. Next thing I knew, the needle on the ammeter went to the extreme left, indicating either a short, or a load. Seems to be intermittent. Would you know which electronic compotent could be the culprit? Many thanks, Erick :)
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Erick, this engine has two wires coming out from behind the shroud as well. I have tractors that only have one wire also. One wire goes directly inside the points cover the other goes on oneside of the bakelite tab and the white kill wire goes on the otherside of the bakelite tab. If that tab was metal on yours that is difinitely the reason it wouldn`t run. You can cut a old piece of plastic and it would serve the same purpose as the bakelite. I have a tractor where I simply hooked the kill wire from the key switch to the other (extra) wire coming from behind the shroud together with and electrical connector and it works fine that way as well. In the picture you should beable to see the two wires coming out from behind the shroud and the kill wire on one side of the bakelite and the other wire on the other side of the bakelite.
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Ray, Thank you for the picture. That's what I figured. The tab on my tractor is definitely steel, not bakelite. (Previous owner did this.) Right now, I have the kill wire connected to the extra black wire and electrical tape to cover it temporarily for diagnosis purposes. That plastic tab idea is a great one. Will find a piece of temperature-resistant plastic and cut a tab out of it and attach as shown in the picture. Great tip. :) Guys, here's an update: I went through Maynard's diagram much more closely and I noticed that the previous owner had the positive/negative wires reversed on the solenoid. I didn't notice this before because my other tractor has an automobile coil attached to it and the wiring is a little bit different. (I had to find my bearings on the diagram as well.) I reversed the wires back to the way it's supposed to be. The positive is now on the left side, and the negative on the right side. (This is according to the diagram.) After the reversal was done, I tried starting it- and sure enough, it worked! I started it, let it run for 2 minutes... Everything felt physically cool, nothing was hot or smoking. I turned it off with no problems. Then I turned it back on, turned it off, worked great... Turned it on again, then all of suddendly, the fuse blew. Suspecting that it was due to turning the ignition on and off several times, I touched the two ends of the wires, bypassing the fuse... It went to the extreme left and started to short again. *Sigh* It seems that something is faulty... And working intermittenly. Any idea which electronic compotent could be the culprit? (I would guess the voltage regulator?) The solenoid has been tested, and it works. Starter generator is in great shape and works correctly. The points/condensor is brand new. Wiring is brand new. That leaves the ammeter and the voltage regulator in question. It looks like my next step is to change the ammeter just to be on the safe side, and see how that goes. I wanted to thank you all again, for all this help. I'm working hard, doing my best to make the effort you guys put into helping me worthwhile. I really appreciate it. :)
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