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patrick78

Electrical Help

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patrick78
I have an early model B10. I bought it last spring. Early this summer i was cutting grass and it cut off. This tractor has been converted to a 12 hp motor from the same type simplicity tractor. So the wiring is not stock, but not "birdnested" either. This motor was converted to an external 12 voly coil. It still has the stock key switch, and push button start. No follow to this date. I cannot get spark at the spark plug on the tractor I replaced the coil on the tractor, and and noticed when i pulled the points cover, it did not have a condensor. How could this be? Can some one give me a good wiring diagram for a garden tractor that has been converted to a 12 volt coil that is exactly like mine? Can someone please give me a walk through to check where the problem is? I love this tractor, and I have been stuck cutting my large yard with a lawn machine (and it sucks). Any help would be greatly appreciated.....

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Vassal
A few thoughts; The main purpose of the condenser is to minimizes arcing across the points, thereby extending their life. I would first take a look at the point contacts to see if they are pitted, crusty etc. Also check the wiring to and from the points and coil etc... You might find a ballast resistor somewhere in the + feed to the coil. If the resistor failed (cooked?), it would open the circuit and the coil would not fire. I can't help with an exact schematic for your machine, but I can scare up a generic battery ignition diagram if needed.

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Vassal
I just found the bookmark to battery ignition bliss courtesy of Maynard (UCD). Although your exact wiring may not be represented, he pretty much covers it all with the diagrams. Check it out: [url]http://www.simpletractors.com/club2/topic.asp?TOPIC_ID=43560[/url]

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D-17_Dave
You state it still has the original style ignition switch. Since this type system,(magneto) uses a grounding switch to kill the ignition and the new style automotive coil uses a 12vdc hot lead to supply voltage to the coil the switch is either different or has been bypassed and is no longer used. I have seen a switch that looks just like the one wire kill switch but had two post's on it that would work. This in mind lets just skip to diagnostics. Is there any other switch on the dash that is wired into the supply line to the + side of the coil? If so is it on and supplying voltage to the coil? This question revolves around the fact that the coil must have 12vDC+ at the + side of the coil for it to fire. If there is no voltage then trace out why. If you do have voltage then disconnect the wire to the points at the - side of the coil. With the power on, touch the post of the - side of the coil to ground repeatedly and see if the plug fires with the plug lying on top of the head. If it doesn't then you have a bad coil, if it does then go to the points or the wire to the points. A side note is that the condenser does stabilise the secondary voltage and keep the points from burning prematurely. A side to this is that it keeps the timing stabil also. It doesn't matter where the condenser is mounted, as long as there is one somewhere in the secondary line and it's chassis grounded. It's common to find them mounted right at the coil or at the points. If you have voltage to the coil, and your firing the plug by bypassing the points, then you likely have dirty points. You'll also need to make sure that the magneto is disconected from the new setup. Hope I made some sense and that this helps you to understand.

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mohrds
This "How To" article may also help as it discusses bypassing the magneto with a coil and lists parts. http://www.simpletractors.com/do_it/magneto_to_coil.htm Doug

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patrick78
Digging around in the wiring harness i found a blown fuse, that looks like it runs to the negative side of the amp meter.....does this have anything to do with the tractor firing or not

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PhanDad
Good chance the blown fuse prevents the +12v from reaching the + side of the coil. As D-17 Dave explained, if you don't have +12v at the coil, it's not going to fire. If you don't have a DC voltmeter, then a 12v test lite can be used to follow the "voltage path" from the battery + terminal all the way to the + side of the coil.

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