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Wisconsin S-7D Motor refusing to start

20282 Views 56 Replies 10 Participants Last post by  Fcubman
I'm still scratching my head with this one. From my bush hog D4-7. Finally got it to turn over and now it's not starting. Fresh battery, new spark plug, fuel, carb cleaner, engine starting spray, nothing. It just keeps turnin and turnin.

From all of that (not being a master of engines by any means), I would assume it's not getting a spark, no spark not from lack of fuel. So the distributor maybe? No power to that?

What do you guys think? Thank you all for your time.
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Couple of questions.

1. This doesn't have a key. I keep reading about a key type ignition and this has no key. Would not having a key or ignition switch prevent this from starting?

2. Can someone post some photos of the area I am working on so I have a reference? I think I have the timing right, still no luck starting it. Some photos would be great! I want to be sure everything's there. Thank you!
And is there a way I can get a distributor for this? I saw this,

And would much rather have that over the current setup.
AFAIK, that was never used on an "S" series Wisconsin. There is no provision to drive it. The setup you have is all you need, you just have to finish troubleshooting it.

Not having an ignition switch will keep it from starting, unless you have another way to get 12V to the "+" terminal on the coil.
Well I need a new coil now, found a large crack under it. Would I have any luck on here finding one? It's a Delco Remy.

The positive wire goes from the battery, to the starter button, goes over to the volt meter, over to the coil. It all connects and gets voltage.

I'm hoping someone will be nice enough to take some photos for me. I searched all over the internet and can't find a darn thing.
So I'm going to need a starter switch too?
I'm concerned that the grounding 'leaf' spring is shy on your setup; I'd be concerned that one of the squirrels was not in the trees & had the terminal stud out of the 'box', lost the spring, & perhaps got the insulators for the terminal stud miss-located in a way that kept a ground on the terminal stud at all times. With the ignition switch being shy, this condition would bust coils with regularity (useta bust Harley coils when I'd forget to turn the switch 'off' after setting solid lifters, but the expense 'learned me'). You know, the line drawing might be for a mag application rather than a battery/coil setup. The grounding spring wouldn't be necessary with an ignition switch present & a switch would take the probability of destroying coils out of the equation (if used!).:fing20:
HD, so you think this motor once had a mag rather than a coil? At some point the coil was added?


I found this motor locally and was wondering if it would work for my tractor. Or just for parts. Seller doesn't know what model it is but it comes with a Magneto. They wrote me this

Old wisconsin single cylinder engine with gear reduction.Engine has been sitting,still turns over.
Thoughts? It's for $25 and an hour drive.
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HD, so you think this motor once had a mag rather than a coil? At some point the coil was added?

I found this motor locally and was wondering if it would work for my tractor. Or just for parts. Seller doesn't know what model it is but it comes with a Magneto. They wrote me this
Thoughts? It's for $25 and an hour drive.
No, after considering the grounding spring being shy & the presence of the coil, I began to wonder if this engine hadn't started life as Battery/Coil & had the ignition switch removed (for whatever reason). With full time power 'on' & a continuous ground on ignition's primary side, you cannot help failing the coil. I've had remarkable success by Google searching using a part number & the company's name which issued the number. I'm betting that search will either find you a replacement, or a substitute.

The gear-reduction aspect is problematic, but the price for parts is attractive (if the engine turns through & has ANY sign of compression). You might want to take a mite of oil & a few appropriate tools with you. The time & gas? Negligible, in my book (as long as I don't encounter a really bad omen en route). Being up for a spot of adventure 'makes' life. Besides, you never know what's waiting for you to trip over it, around the corner.:fing32:
That carb looks like $25, to me. All else would be GRAVY, & there IS the facility of being able to convert from the reduced condition! I'd go for it!, disappointments linger a while, but opportunities 'passed up' nag for much longer!
Well sadly the engine has sold. I'll continue to be on the lookout for these motors on CL and ebay. H-D I don't know the part number for that coil, I'll continue to look for it and photos since no one had posted on here.
And bringing this back from the dead. Brought the tractor out due to good weather :)

Still won't start. The Delco-Remy coil was or had cracked over the winter and is no longer good. In the time since my last update with this, I acquired a TR10-D Wisconsin motor. I noticed with that, that the spark plugs spark comes from inside the motor, I haven't torn into the motor yet to find out where or if it will work on this S-7D motor.

The coil I found out is or was this model:

I currently have another coil for this motor, but I am not producing any spark. I am showing current of 12v to the spark plug but when I turn it on, I get no spark. My ground is good and it looks to be hooked up correctly. What are your thoughts as I'm scratching my head with this one. Thank you!
I'd try replacing the original condensor with one designed for the coil,which appears to me to be an old GM car coil that had point style might be the original condensor that was used in the magneto died after long use (or sitting) with 12V going in it ! do not need to ount the condensor where the old one went,just run the wire on it to the negative terminal on the coil (after disconnecting the old condensor!) and ground the clamp that goes around the condensor to a good ground in a convenient spot away from heat...I bet with a good coil &new condensor she'll fire up!..

I had the same tractor years ago with a S-7-D Wisconsin 7.25 HP engine...someone converted yours to use a car coil,it had a magneto originally...nothing wrong with using a car coil,I think its more reliable in the end..sounds like you need to add an ignition switch to kill power to the coil though,you dont want it staying on constantly,it'll smoke the points & the coil eventually...

Oh yeah,that coil is designed to have a resistor in the wire from the battery that goes to the positive coil terminal...GM used special resistance wire,but a ballast resistor off a 70's Mopar car will work fine--without one,the points can burn up fast and the coil might get hot and fail eventually...
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In case it has been missed, somewhere. The battery supplied 12v to the coil, through the switch, gauge, whatever, resistor. The 12v goes through the coil, through closed points to ground. It builds up a magnetic field. When the points open, the magnetic field collapses. When it collapses, it forces electricity to flow through the spark plug wire, to the center of the plug, jumps the gap and flows to the head, ground.
The resistor makes the amperage lower, and thus not so much flows through the points, and thus less wear when you get that little 'titch' noise caused by the spark of the points opening. The condenser also absorbs some of that juice, as it wants to keep going, but can't, so side-tracks into the condenser, only to be let out again when the points close once more.
Sorry for the long-winded exposition, but I hope it clears up what is going on in a 'kettering' [I think] spark system. A magneto just creates the EMF [magnetic field] by rotating a magnet on the flywheel past a fixed field, and then dumps the magnetic field the same way, via points to ground opening. I think.
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I have 3 coils that came from working tractors, none are producing a spark. I checked my wiring and voltage and it all drops off when I press the button and the motor turns over.

Does anyone have a photo or wiring diagram for the coil so I can double check my wiring?
The positive wire goes from the battery, to the starter button, goes over to the volt meter, over to the coil. It all connects and gets voltage.

Titus,I think that might be your problem,feeding the coil through the starter button.You need a seperate toggle switch for the coil.Just an ON-OFF,two terminal toggle switch.Wire one terminal to battery positive and the other to the positive side of coil.Disconnect the wire from coil to volt meter.Turn toggle switch on and hit starter button and you should have spark.Turn off toggle to kill engine.
Here's the wiring photos from today:

I tried what you said and following the wiring diagram, how can I connect to the condenser then ground? I still got no spark today :( What am I doing wrong?
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That red alligator clip is going to the toggle switch pos to the coil pos. The black is going to the bottom where it was when the last coil was on as you can see. Am I not grounding something?
I have a kill switch and the wiring has been checked, 12V checked and dead when the switch is flipped. So I know that's working.
In the breaker box in the last photo above you can see the blk alligator clip. That's going to my neg side of the coil. I've noticed when doing this, I'm getting 12V consistently.

Now if I add a 2nd alligator clip on the same screw as the black on and ground it, I drop down to 1 or 2 volts.

The condenser is getting 12vs, the coil wire that goes from the coil to my spark plug is getting 12V consistently.

I press the start button with the switch being on and voltage drops and still no spark.

I followed that wiring diagram above, and breaker points are correct and grounded inside itself from the screw. That diagram says I should ground the condenser, to where? I've tried the neg on the coil and that doesn't work.

As you can tell, I'm at a loss with this thing. :(

Not giving up, but frustrated to say the least. What are your thoughts?
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I got totally confused reading this, so I'll offer this advice: Take a voltmeter, clip the (-) to the negative side of the battery itself. With your ignition switch on, you should have B+ (battery voltage) on the + side of the coil all the time. With the points open, you should have B+ on the - side of the coil. With the points closed, you should have close to 0 volts on the - side of the coil. The diagram TOM603 posted is correct.
If you don't get these voltage readings, post what you get and where. This is not rocket science, but does need a logical approach, and we'll help as we can.

The condenser should be grounded to machine ground.

Reading your post #38, it appears that the points are not grounding the coil primary circuit. When the points close, they ground the coil primary circuit. When they open, they break the circuit, inducing the high voltage out of the coil secondary.

The 12v on the coil secondary is also confusing. The coil body needs to be grounded to the engine, as do the condenser and one side of the points.

Please post the voltages at the various places I mentioned, and we'll go from there.
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