Spark....no spark.....spark....

[Clem]

I have a brain teaser for you:

While idling and running smooth my tractor stalled out.

I tried to start it and it turned smoothly and fired jsut briefly

I got it into the shop and detached each plug and reconnected, then pulled one plug and grounded it and watched it spark as the engine turned over.

I reapplied it and the engine fired briefly then stopped. I removed the plug, grounded it and turned the engine over. No fire.

We then removed the distributor cap and cleaned it as well as the magneto and points. we layed all the spark plugs on their sides and hand cranked and watched each one spark in proper order.

We reassembled and after a short fire of the engine, it stopped and again no spark.

My rotor and pinion gears are missing 1 1/2 teeth, however they have always been that way. other than that no other damage is seen.


thanks. Clem

[Rob in NH]

i had the same problem, on mine it was the key switch.use a test lite on it to see if its working, thats if you have a key.

[Bigdog]

Whether you have a magneto or battery ignition the problem may be the switch as Clem suggests. The mag switch is a grounding switch and if the wire from the switch to the mag distributor side terminal is frayed anywhere it can ground out. This commonly happens next to the dash panel where you foot can cause the wire to rub against the edge of the panel. A quick check for that is to disconnect the wire at the distributor and see if that cures the problem.
If you have a battery ignition, a couple of quick checks with a voltmeter will tell you if you have voltage to the coil primary when there is no spark.

[John *.?-!.* cub owner]

A bad coil as well as a loose wire has also been known to give the smae problems

[beaconlight]

Yes to what the guys have posted. A condenser can be a culprit in this typw of trouble too.

Bill

[allenlook]

All my tractors are set to stop sparking whenever the Cub Locator Beacon goes overhead

So far... so good.

[Bigdog]

I guess what we are saying is that there are a number of possible causes for this problem. A little deductive reasoning and troubleshooting should easily find the source.

[Clem]

i am sorry I should have added that I did disconnect the wire to the switch and magneto as you guys suggested. I did take the condesor out to replace it tonight, since they are cheap.

[Bigdog]

The distributor cap is another possible source for your problem. Intermittant problems can be a challenge but it is very satisfying when you solve one of them.

[Donny M]

While inside the mag replacing the condenser you may also want to check the wire from the coil to the points. If the rubber grommet where the wire passes through the mag body is compromised the wire can short to the body. Just something to check while your there.

[Clem]

The problem is solved. We cleaned all of the parts in the mag and distributor. We also discovered that the felt washers were missing. The tractor is running great now.


thanks

['Country' Elliott]

Hey Clem...Ain't it frustratin' to have a POSATIVE ground electrical system and findin' out that it's just a matter of CLEANIN all the connections to make sure it's groundin' properly in order to START !!!! (BUT...It SURE BEATS spendin' all that money on NEW plugs, NEW points, NEW condensor, NEW magneto cap...etc.!!! )

[Clem]

You know....It takes a while to get it through my thick skull to check ground first no matter what!

[John(videodoc)]

been there, done that, learned that. But one thing is for sure, after the learning experience, i will always check that first.