Screaming electrical

[CubHunter]

All the wiring is good and checks out, and have proper amps and voltage to distributer. Points are gapped properly condenser and points are new. Plugs are new and gapped properly. Still no spark......and my other mower just went down. Thses gremlins are getting on my last Yankee nerve.....

[Slim140]

Coil wire plugged in good to the cap and coil? Take the cap off and spin it over with switch on and see if you have any spark at the points.

[Landreo]

No spark where? At the spark plugs or out of the coil center terminal? You remembered to put the rotor back in? I have tried to start cubs without the rotor in place and they do not start!

With the ignition on, the cap removed, hold the secondary wire from the coil center terminal close to a ground such as the frame, points closed, just flick the points open with your finger and you should see a spark from the coil secondary wire the frame. You may see a spark also from the points or you may not, don't worry about that part. You may also feel a small jolt from the points on your finger, don't worry about that. Worry about the spark jumping from the coil center terminal. No spark but 6 or 12 volts to the coil then I would put an ohm meter on the center terminal of the coil to one of the coil primary terminals, does not matter which one. Ignition off of course. You may just have a bad coil if the other voltages are truly correct as you posted.

[CubHunter]

The coil is new and checks out on the ohms, the point are sparking when closed!?!

[Smokeycub]

...well, something is wrong. If you're working on your 48 Cub then obviously it was converted to a non-mag coil. It's been said numerous times that because a coil is new doesn't mean it's good. I would try a different coil just to see. Another place to check is the power lead to the distributor, sometimes they short out where the wire enters through the side and the short may be intermittent. What part exactly is screaming?? lol

[CubHunter]

Me, and I checked the coil and regulator on the multimeter, they are both up to spec.

[Landreo]

No spark where? At the spark plugs or out of the coil center terminal?

With the ignition on, the cap removed, hold the secondary wire from the coil center terminal close to a ground such as the frame, points closed, just flick the points open with your finger and you should see a spark from the coil secondary wire the frame. You may see a spark also from the points or you may not, don't worry about that part. You may also feel a small jolt from the points on your finger, don't worry about that. Worry about the spark jumping from the coil center terminal. No spark but 6 or 12 volts to the coil then I would put an ohm meter on the center terminal of the coil to one of the coil primary terminals, does not matter which one. Ignition off of course. You may just have a bad coil if the other voltages are truly correct as you posted.

A quote from my previous post. Where the spark is stopped, at the coil, distributor, plugs, plug wires or where ever makes the diagnosis of the problem easier. If there is spark out of the secondary of the coil then look at the rotor, cap, cap alignment, etc.

A spark to the points is useful information but what is happening at the coil? Flicking the points open will quickly answer that question and likely eliminate the coil from consideration. The rotor also has to be aligned with the correct post in the distributor cap otherwise the spark has no where to go.

The points should not spark when closed, they may be dirty. They can spark when opening or closing but once closed they should not spark.

[Smokeycub]

Just curious, was the tractor running and just quit? ...or what, exactly, happened. Once you see the coil is actually producing spark and still no joy at the plugs then it's a matter of timing as long as the cap, rotor, and wires are good.

[Willy]

I've had brand new coils give me fits. One that comes readily to mind, the + and - markings on it were backwards straight out of the box new. I wired it up according to the markings, no joy and lost a few days trying to sort it out. Finally, a friend asked if I'd tried reversing the wires. Having nothing to lose, I did and the engine fired right up.

On my Cub, when I was getting it running again last fall, I didn't look too closely at the points other than a quick check for corrosion when I was trying to get it fired up again. The engine ran great when it was originally parked in '04 after an overhaul and for the short run in '12 it had. It didn't even try to fire until I regapped the points this time around.