Mag Hot / Mag Cold Problem

[loveshisallis]

I have a FM J magneto that has been giving me problems like this.
I check fo rspark off the coil and I have all the spark you could want . the I time the cap and reinstall everything.
Then , I may or no have spark at the end of the plug wire. Then after the tractor ties to start but wont, I pull the wire and crank. Again no spark!I have checked the wiring and timing inside the mag and found nothing obvious wrong.
I could use some helpful advice as to what is what here.
Really appreciate the help

 

[greygoat]

I bought a 2 Cyl Wisconsin engine from an Amish
gentleman, who was mad because it wouldn't start
again when shut off hot. An Old magneto man who
I met at an engine show said,"weak coil". I put
in a new coil and it's been starting fine ever since. It had spark, even when hot, but maybe
not enough to fire the plug under compression.
Wico and Fairbanks-Morse magneto coils,points,
condensers are still available from Steiner, at
www.external_link, or nnalert at
www.nnalert.com. possibly from Yesterdays
Tractor Co. Sorry, I just haven't checked this
website for Magneto Parts

 

[greygoat]

Just checked YT, Tractor Parts, Electrical,
search all make for "magneto". Found lots of
magneto parts.
Remember, the parts are specific to the MAKE OF
MAGNETO, more so than the make of tractor. A
Fairbanks-Morse or Wico magneto on a Allis,
or a Case will usually have the same internal
parts, as log as it's a 4 cyl magneto.