naa ignition switch

An ignition switch can fail under any condition, especially on an open tractor out in the weather and dirt.

A simple test light is all you need to check for power at the coil when it won't start. Otherwise, it's guesswork, throwing parts at it, possibly creating more problems!
 
It seems unlikely. The keyed switch only supplies voltage to the coil at a few amps so there isnt (or shouldnt be!) a lot of heat-generating resistance going through the switch and wires . An old, original switch can have worn internal contact points and that could cause intermittent problems.

If you suspect the switch, just jump across the two wires on it the next time it quits- if it works then, I would definitely replace it.
 
If it runs until warm, then quits, but will restart after ''cooling down'', I'd suspect a faulty condensor- or maybe restricted fuel flow...
 
Sure an ignition switch can fail maybe develop resistive contacts perhaps get worse when warm HOWEVER other warm temperature related problems might be the ignition coil or condensor or even the points. If it starts better if you were to hot wire the coil that cuts towards the switch contacts being bad/resistive and the problem. Still first suspects are the coil or condensor.

John T
 
yes.... I see it quite often on the pre 65 tractors... but usually wiggling the switch will show it going off and on. SO it will sit there and idle and all of a sudden cut off,,, due to vibration or heat, or dirty contacts, or the sign of the moon phase. Someone who runs a heavy key ring with lots of keys on it will usually see this problem sooner than others.
 
So does the tractor stop running or it is exactly as you have described the tractor is shut off but then you restart it right away? Is the tractor an original 6 volt system? Many times on those the starter gets worn and draggy and uses more amps then it should. This in turn drops the voltage to the ignition coil keeping it firing the ignition for starting. You should take a voltmeter and read the voltage at the coil while you are cranking the starter during one of these episodes and report back. Also someone installing battery cables that are to light ..not able to carry the proper amperes.. is another common cause of your problem.
 
You need an ignition on indicator light, on my 41 9-N i put a small led light wired to ignition switch. It is the FIRST check with no start, no light = no power to coil. On my Jubilees I wired the dash lights in the oil pressure and amp gauges to come on with the ignition switch. You have to look for the light but serves as an ignition on indicator light. My 39 9-N came with a red indicator light, it must have cost too much and Henry deleted it. joe
 
It must have cost too much and Henry deleted it.
Yeh that red jeweled light must have cost a hole .25 cents at the time. :lol: Original lite is a unattainable high dollar lite now days. :lol:

This post was edited by Den N Ms on 05/19/2022 at 03:22 pm.
 
Simple test, when it won't start snap the clips of a test lead between the hot and if ignition terminals on the switch and try starting it again.
 

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