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Wisconsin S-7D Motor refusing to start

20313 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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When you pull it over you should hear a "clack" coming from the magneto,that is a spring loaded impulse coupling that spins the magneto shaft rapidly to give it a hotter spark for starting..the points have to be set properly,turn the engine slow by hand and watch the points--when they open to the widest gap,that is where the engine needs to be at,when setting the gap,otherwise they wont open at the correct time or might not ever should see a healthy blue spark each time the impulse coupling "snaps"...
Many Wisconsins used 18mm plugs,and they dont always weather well,might want to try a new plug ,that might be all it needs..I think the SD-7 I had took a D16 Champion...
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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