9N starting help please

Hi - on the weekend I was helping a friend with his 9N - it's a 12 v conversion, front mounted distributor. Basically the machine would crank but not start - though with a pull start it ran like a top. Here's what I've checked so far:

- battery was undercharged - that's being corrected
- no spark so I traced back to find the ballast coil side dead - getting a new one
- haven't checked the alternator charging but given the state of the battery I suspect it was not charging
- haven't put the multimeter on the coil yet

So some questions:

- once I get the ballast and have the battery charged is there a particular order of checks or prodedures to diagnose what went wrong ?

- if the coil or alternator are fried is there a root cause to correct

Thanks in advance

Steve

If it started w/ a pull but not off the starter, chances are the root cause was that weak battery. It started w/ a pull because all of the limited battery voltage went to the coil.

" the ballast coil side dead - getting a new one"

I'm not sure what you are saying here.

What was the voltage at the top of the coil?

Are you getting a new ballast resistor or a new coil?

You can temporarily jump the ballast resistor.

And speaking of resistors.....because it's a 12v conversion....if it's a 12v coil, all you need is the OEM ballast resistor, as in the picture.

Is that the only resistor in the circuit?

" - once I get the ballast and have the battery charged is there a particular order of checks or prodedures to diagnose what went wrong ?"

Yes.

Check the voltage w/ the points open & pints closed. Points open, 12.35v; closed, 9 or so volts.

" - if the coil or alternator are fried is there a root cause to correct"

What fries one doesn't fry the other. The circuits are separate.

The usual cause of alternators going dead is they just go bad. And, reversing polarity on a jump start or battery installation.

The usual cause of front coil failure is leaving the key on (see tip # 38) or a poorly done 12v conversion that allows too much running current to the coil.

Post back w/ results or more questions.

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